Analysis system, analysis method, and analysis program

Abstract

To speedily predict structure of a product obtained from at least one kind of reactant.SOLUTION: An analysis system acquires at least one kind of reactant. For each of at least one kind of reactant, at least one hydrogen atom contained in the reactants contains at least one hydrogen atom coupled to the carbon atom of the reactants. The analysis system converts the respective reactants to virtual reactants in which the coupling carton atoms and hydrogen atoms are coupled to one virtual atom, generates a reaction system in which at least one virtual reactant is disposed for each of at least one kind of virtual reactant, acquires an object reaction formula for obtaining a product from at least one kind of reactant, executes a molecular dynamics calculation based on at least one kind of virtual reactant within the reaction system, and executes substitution treatment for substituting a virtual product for at least one virtual reactant in which it is estimated that a chemical reaction shown by the object reaction formula occurs.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] One aspect of the present disclosure relates to an analysis system, an analysis method, and an analysis program. [Background technology]

[0002] Conventionally, methods for predicting the structure of a product obtained from one or more types of reactants have been known. For example, Patent Document 1 describes a method of performing molecular dynamics calculations and executing a reaction process to bond each particle constituting a polymer particle model to a crosslinker particle when the particle approaches the crosslinker particle within a predetermined distance. For example, Non-Patent Document 1 describes a method of searching for one or more reaction candidates in a certain configuration state, selecting one reaction candidate from the one or more reaction candidates, and switching the force field parameters and potential function of the selected reaction candidate to the force field parameters and potential function of the product. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-187189 [Non-patent literature]

[0004] [Non-Patent Document 1] Takuya Fujie, Norio Takenaka, Masataka Nagaoka: “SEI film formation simulation using Red Moon method combined with QM / MM method”, J.Comput.Chem.Jpn., Vol.18, No.1, pp.29-37(2019) Summary of the Invention [Problem to be solved by the invention]

[0005] A method that can rapidly predict the structure of products obtained from one or more types of reactants is desirable. [Means for solving the problem]

[0006] An analysis system according to one aspect of the present disclosure includes at least one processor. The at least one processor acquires one or more types of reactants, each of which includes a plurality of carbon atoms and one or more hydrogen atoms, and for each of the one or more types of reactants, one or more hydrogen atoms included in the reactant include one or more hydrogen atoms bonded to a carbon atom of the reactant, converts each reactant into a virtual reactant in which the bonded carbon atoms and hydrogen atoms are integrated into a single virtual atom, generates a reaction system in which one or more virtual reactants are arranged for each of the one or more types of virtual reactants, acquires a target reaction formula for obtaining a product from the one or more types of reactants, and performs a molecular dynamics calculation based on the one or more types of virtual reactants in the reaction system to perform a substitution process in which the one or more virtual reactants in which a chemical reaction represented by the target reaction formula is predicted to occur are replaced with a virtual product.

[0007] An analytical method according to one aspect of the present disclosure is implemented by an analytical system including at least one processor. The analytical method includes the steps of: acquiring one or more types of reactants, each of the one or more types of reactants including a plurality of carbon atoms and one or more hydrogen atoms, and for each of the one or more types of reactants, one or more hydrogen atoms included in the reactant including one or more hydrogen atoms bonded to a carbon atom of the reactant; converting each reactant into a virtual reactant in which the bonded carbon atoms and hydrogen atoms are integrated into a single virtual atom; generating a reaction system in which one or more virtual reactants are arranged for each of the one or more types of virtual reactants; acquiring a target reaction formula for obtaining a product from the one or more types of reactants; and performing a substitution process by performing a molecular dynamics calculation based on the one or more types of virtual reactants in the reaction system to replace one or more virtual reactants that are estimated to cause a chemical reaction represented by the target reaction formula with virtual products.

[0008] An analysis program according to one aspect of the present disclosure causes a computer to execute the following steps: acquiring one or more types of reactants, each of which contains a plurality of carbon atoms and one or more hydrogen atoms, and for each of the one or more types of reactants, one or more hydrogen atoms contained in the reactant include one or more hydrogen atoms bonded to a carbon atom of the reactant; converting each reactant into a virtual reactant in which the bonded carbon atoms and hydrogen atoms are integrated into a single virtual atom; generating a reaction system in which one or more virtual reactants are arranged for each of the one or more types of virtual reactants; acquiring a target reaction formula for obtaining products from the one or more types of reactants; and performing a substitution process by performing molecular dynamics calculations based on the one or more types of virtual reactants in the reaction system to replace one or more virtual reactants that are estimated to cause a chemical reaction represented by the target reaction formula with virtual products.

[0009] In one aspect of the present disclosure, each of one or more types of reactants is converted into a virtual reactant, which is a combination of bonded hydrogen atoms and carbon atoms. Then, through a substitution process using molecular dynamics calculations, one or more virtual reactants that are estimated to cause a chemical reaction represented by a target reaction formula are replaced with virtual products. By simplifying the reactant structures in this way and then performing the substitution process using molecular dynamics calculations, the time required for the molecular dynamics calculations can be shortened compared to when the substitution process is performed while taking into account the structures of each reactant as they are. Consequently, the structure of the product obtained from one or more types of reactants can be predicted more quickly. [Effects of the Invention]

[0010] According to one aspect of the present disclosure, the structure of a product obtained from one or more types of reactants can be predicted quickly. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 2 illustrates an example of a functional configuration of an analysis system. [Figure 2]FIG. 2 is a diagram illustrating an example of a hardware configuration of a computer that constitutes the analysis system. [Figure 3] 10 is a flowchart illustrating an example of the operation of the analysis system. [Figure 4] FIG. 1 is a diagram schematically illustrating the relationship between a reactant and a virtual reactant. [Figure 5] 10 is a flowchart illustrating an example of a replacement process. [Figure 6] FIG. 1 is a diagram showing an example of a reaction formula. DETAILED DESCRIPTION OF THE INVENTION

[0012] Various examples of the present disclosure will be described in detail below with reference to the accompanying drawings. In the description of the drawings, the same or equivalent elements are designated by the same reference numerals, and redundant description will be omitted.

[0013] [System Overview] The analysis system according to the present disclosure is a computer system that performs analysis of chemical reactions involving one or more types of reactants. In this disclosure, a reactant refers to a compound containing multiple carbon atoms and one or more hydrogen atoms. In one example, the one or more hydrogen atoms include one or more hydrogen atoms bonded to a heteroatom of the reactant and one or more hydrogen atoms bonded to a carbon atom. In this disclosure, a hydrogen atom bonded to a heteroatom of the reactant is referred to as a first hydrogen atom, and a hydrogen atom bonded to a carbon atom is referred to as a second hydrogen atom. Here, a heteroatom is an atom other than a carbon atom and a hydrogen atom, and examples thereof include a nitrogen atom and an oxygen atom. The one or more hydrogen atoms do not necessarily include the first hydrogen atom.

[0014] In the present disclosure, a chemical reaction may occur between multiple types of reactants or only one type of reactant. Examples of a chemical reaction involving only one type of reactant include a chemical reaction occurring within a single reactant and a chemical reaction occurring between two or more reactants of the same type. Examples of a chemical reaction occurring within a single reactant include a chemical reaction in which a new bond is formed within the single reactant, causing the reactant to change into one product, and a chemical reaction in which an existing bond within the single reactant is cleaved, causing the reactant to split into multiple products.

[0015] In one example, the analytical system predicts the structure of a product obtained from one or more types of reactants. In this disclosure, a product refers to a compound obtained from a chemical reaction involving one or more types of reactants, and the formula representing the chemical reaction is referred to as a reaction equation. One or more types of reactants may result in one type of product, or two or more types of products.

[0016] Each of one or more types of reactants includes, for example, a site involved in the chemical reaction and a remaining site excluding the site. In the present disclosure, the site involved in the chemical reaction is referred to as a reactive site, and the remaining site excluding the reactive site is referred to as a remaining site. The reactive site includes atoms that contribute to the chemical reaction. In the present disclosure, such atoms are referred to as reactive atoms.

[0017] Each of one or more types of reactants contains one or more reactive sites. For example, if a chemical reaction results in the formation of a new bond within a single reactant, that reactant may contain multiple reactive sites. If a chemical reaction results in the cleavage of an existing bond within a single reactant, that reactant may contain at least one reactive site. If a chemical reaction occurs between multiple reactants, either heterogeneous or homogeneous, each reactant may contain one reactive site.

[0018] Each reactive site contains one or more reactive atoms. In the case of a chemical reaction in which an existing bond is cleaved within a single reactant, the reactive site in that reactant contains multiple reactive atoms. For example, the two atoms located on either side of the bond cleavage site constitute the multiple reactive atoms. In the case of a chemical reaction occurring between multiple reactants, either heterogeneous or homogeneous, and in the case of a chemical reaction in which a new bond is formed within a single reactant, each reactive site contains one reactive atom.

[0019] In one example, the analysis system predicts the structure of the product by performing molecular dynamics calculations. Molecular dynamics calculations are a computational method that calculates the forces acting on individual atoms in each reactant and calculates the position and velocity of each atom as a function of time. By performing such molecular dynamics calculations, the analysis system simulates the dynamic behavior of one or more types of reactants in a chemical reaction and predicts the structure of the product obtained as a result of the chemical reaction.

[0020] [System Configuration] An example of application of an analysis system 10 according to an embodiment will be described with reference to Fig. 1. Fig. 1 is a diagram showing an example of the functional configuration of the analysis system 10.

[0021] In one example, the analysis system 10 includes functional modules including an acquisition unit 11, a generation unit 12, an analysis unit 13, and an output unit 14. The acquisition unit 11 is a functional module that acquires one or more types of reactants and a target reaction formula for obtaining a product from those reactants. In the present disclosure, the target reaction formula refers to a reaction formula that is the target of analysis by the analysis system 10. The generation unit 12 is a functional module that generates a reaction system in which molecular dynamics calculations are performed. In the present disclosure, the reaction system refers to a three-dimensional virtual space defined by the analysis system 10. The analysis unit 13 is a functional module that predicts the structure of a product obtained from one or more types of reactants through a chemical reaction represented by the target reaction formula. The output unit 14 is a functional module that outputs processing results.

[0022] FIG. 2 is a diagram showing an example of the hardware configuration of a computer 100 constituting the analysis system 10. For example, the computer 100 includes a processor 101, a main memory 102, an auxiliary memory 103, a communication control unit 104, an input device 105, and an output device 106. The processor 101 executes an operating system and application programs. The main memory 102 is composed of, for example, ROM and RAM. The auxiliary memory 103 is composed of, for example, a hard disk or flash memory, and generally stores larger amounts of data than the main memory 102. The communication control unit 104 is composed of, for example, a network card or a wireless communication module. The input device 105 is composed of, for example, a keyboard, a mouse, a touch panel, etc. The output device 106 is composed of, for example, a monitor and speakers.

[0023] Each functional module of the analysis system 10 is realized by an analysis program 110 pre-stored in the auxiliary storage unit 103. Each functional module is realized by loading the analysis program 110 onto the processor 101 or the main storage unit 102 and having the processor 101 execute the analysis program 110. In accordance with the analysis program 110, the processor 101 operates the communication control unit 104, the input device 105, or the output device 106 to read and write data from and to the main storage unit 102 or the auxiliary storage unit 103.

[0024] The analysis program 110 may be provided in the form of being recorded on a non-transitory recording medium such as a CD-ROM, a DVD-ROM, a semiconductor memory, etc. Alternatively, the analysis program 110 may be provided via a communication network as a data signal superimposed on a carrier wave.

[0025] The analysis system 10 may be configured with one computer 100 or multiple computers 100. When multiple computers 100 are used, these computers 100 are connected via a communication network such as the Internet or an intranet to logically construct a single analysis system 10. The analysis system 10 may also be constructed by combining multiple types of computers.

[0026] [System Operation] An example of processing by the analysis system 10 and an analysis method according to the present disclosure will be described with reference to Fig. 3. Fig. 3 is a flowchart showing an example of processing by the analysis system 10.

[0027] In step S1, the acquisition unit 11 acquires one or more types of reactants. The acquisition unit 11 may acquire one or more types of reactants input by a user operation, or may receive one or more types of reactants from another computer system.

[0028] In step S2, the generation unit 12 converts each reactant into a virtual reactant. In one example, the generation unit 12 combines the bonded carbon atom and hydrogen atom (second hydrogen atom) contained in each reactant into one. In the present disclosure, an atom formed by combining the bonded carbon atom and second hydrogen atom is referred to as a virtual atom, and a virtual reactant refers to a reactant in which the bonded carbon atom and second hydrogen atom contained in the reactant are converted into virtual atoms. Here, the number of second hydrogen atoms bonded to one carbon atom may be one or more.

[0029] An example of a reactant and a virtual reactant converted from the reactant will now be described with reference to Fig. 4. Fig. 4 is a diagram schematically showing the relationship between a reactant and a virtual reactant.

[0030] The example shown in FIG. 4 shows reactant 200 having at least a structure in which one carbon atom 201 is bonded to two second hydrogen atoms 202 in a series, and virtual reactant 300 converted from reactant 200. Note that the structures shown in FIG. 4 are merely a portion of reactant 200 and virtual reactant 300. In this example, reactant 200 is converted into virtual reactant 300 by combining the above-mentioned bonded one carbon atom 201 and two second hydrogen atoms 202 into one virtual atom 301. That is, in this example, a total of three atoms are combined into one virtual atom 301. In this way, in step S2, a structure consisting of multiple atoms is converted into a structure consisting of one atom, so the conversion from the product to the virtual reactant can also be said to be a simplification of the reactant structure.

[0031] In step S3, the generation unit 12 generates a reaction system. In one example, the generation unit 12 generates a reaction system in which one or more virtual reactants are arranged for each of one or more types of virtual reactants. In this example, the generation unit 12 may generate a reaction system in which, in addition to the virtual reactants, another compound that does not contribute to the chemical reaction of one or more types of reactants is arranged. The another compound may be, for example, a solvent for promoting the chemical reaction of one or more types of reactants.

[0032] When a chemical reaction involving one or more types of reactants is carried out, it is common to use other compounds, such as a solvent, in addition to the reactants. Therefore, as described above, by adding another compound, such as a solvent, that does not contribute to the chemical reaction to the reaction system, it is possible to predict the structure of the product under conditions that are close to the actual situation.

[0033] In step S4, the acquisition unit 11 acquires a target reaction formula. In one example, the acquisition unit 11 acquires the target reaction formula by referring to a database that stores multiple reaction formulas. In the database, each reaction formula is stored in association with one or more types of reactants. In other words, the database can be said to be a device that stores data including data records that indicate combinations of reaction formulas and one or more types of reactants indicated in the reaction formula. In this example, the acquisition unit 11 acquires, as the target reaction formula, a reaction formula corresponding to one or more types of virtual reactants arranged in the reaction system from among the multiple reaction formulas stored in the database. In this case, the acquisition unit 11 may acquire only one reaction formula as the target reaction formula, or may acquire multiple reaction formulas as the target reaction formula, depending on the types of the virtual reactants. The acquisition unit 11 may acquire a target reaction formula input by a user operation, or may receive a target reaction formula from another computer system.

[0034] In step S5, the analysis unit 13 executes a molecular dynamics calculation to perform a substitution process for substituting a predetermined virtual reactant with a virtual product. In the present disclosure, the virtual product refers to a product in which the carbon atom and the second hydrogen atom that are bonded to each other among the atoms contained in the product are converted into virtual atoms.

[0035] In one example, the analysis unit 13 performs molecular dynamics calculations based on one or more types of virtual reactants in the reaction system, and replaces one or more virtual reactants in which a chemical reaction represented by the target reaction formula is estimated to occur with virtual products. In this example, the number of virtual reactants to be converted into virtual products is determined depending on the chemical reaction represented by the target reaction formula. For example, in the case of a chemical reaction occurring between multiple reactants of the same or different types, the analysis unit 13 converts a combination of virtual reactants in which the chemical reaction is estimated to occur (multiple virtual reactants) into virtual products. As another example, in the case of a chemical reaction occurring within a single reactant, the analysis unit 13 converts one virtual reactant in which the chemical reaction is estimated to occur into a virtual product.

[0036] An example of the replacement process will now be described in detail with reference to Fig. 5. Fig. 5 is a flowchart showing an example of the replacement process.

[0037] In step S51, the analysis unit 13 sets a predetermined constraint on one or more types of virtual reactants in the reaction system. In one example, the analysis unit 13 sets a constraint on one or more types of virtual reactants in the reaction system that fixes the distance between a heteroatom and a hydrogen atom (first hydrogen atom) that are bonded to each other. The distance may be a distance based on the bonding relationship between the heteroatom and the first hydrogen atom, or may be, for example, a bond distance that indicates the average distance between the two atoms.

[0038] In step S52, the analysis unit 13 performs a molecular dynamics calculation based on one or more types of virtual reactants in the reaction system under the set constraints. If a reaction system is generated in step S3 in which, in addition to one or more types of reactants, another compound that does not contribute to the chemical reaction is arranged, the analysis unit 13 may perform a molecular dynamics calculation based on the one or more types of virtual reactants in the reaction system and the other compound. In one example, the analysis unit 13 acquires at least the temperature and pressure in the reaction system as calculation conditions and performs the molecular dynamics calculation under those calculation conditions. In this example, the analysis unit 13 may accept, for example, the temperature and pressure input by a user operation as calculation conditions.

[0039] In one example, the analysis unit 13 may execute the molecular dynamics calculation for a time period until the reaction system reaches a stable state. In the present disclosure, a stable state refers to a state in which a predetermined parameter in the reaction system has converged. The predetermined parameter may be the amount of change in energy in the reaction system or the density in the reaction system. Alternatively, the analysis unit 13 may execute the molecular dynamics calculation for a time period set by the user.

[0040] In step S53, the analysis unit 13 calculates the distances between reactant atoms in the reaction system after the molecular dynamics calculation has been performed. In one example, the analysis unit 13 calculates the distances between reactant atoms for all combinations of reactant atoms corresponding to the chemical reaction represented by the target reaction formula, based on the arrangement of each virtual reactant in the reaction system after the molecular dynamics calculation has been performed. In the present disclosure, this distance is also referred to as the "reactant atom distance." In the case of a chemical reaction occurring between multiple reactants of the same or different types, the analysis unit 13 calculates the reactant atom distances for all combinations of virtual reactants. In the case of a chemical reaction occurring within a single reactant, the analysis unit 13 calculates the reactant atom distances in that virtual reactant.

[0041] In step S54, the analysis unit 13 determines whether there are one or more virtual reactants whose calculated interatomic distances satisfy a predetermined condition. In one example, the predetermined condition is defined by the relationship between the interatomic distance and a predetermined threshold. In the case of a chemical reaction occurring between multiple reactants of different types or the same type, the analysis unit 13 determines whether there are combinations of virtual reactants whose interatomic distances are equal to or less than the predetermined threshold. In the case of a chemical reaction in which a new bond is formed within a single reactant, the analysis unit 13 determines whether there are virtual reactants whose interatomic distances are equal to or less than the predetermined threshold. In the case of a chemical reaction in which an existing bond is cleaved within a single reactant, the analysis unit 13 determines whether there are virtual reactants whose interatomic distances are equal to or greater than the predetermined threshold.

[0042] In one example, the predetermined threshold used for the judgment is set according to the type of chemical reaction represented by the target reaction formula. In the case of a chemical reaction occurring between multiple reactants of the same or different types, and a chemical reaction in which a new bond is formed within a single reactant, the threshold is set based on the van der Waals distance, which indicates the minimum distance at which atoms can approach each other. In this example, the threshold may be set to the van der Waals distance itself, or to 1.2 times the van der Waals distance. In the case of a chemical reaction in which existing bonds are cleaved within a single reactant, the threshold is set based on the covalent bond distance, which indicates the average distance between atoms bonded to each other. In this example, the threshold may be set to the covalent bond distance itself, or to 1.2 times the covalent bond distance.

[0043] If the analysis unit 13 determines that one or more virtual reactants exist whose interatomic distances satisfy the predetermined condition (YES in step S54), the process proceeds to step S55. On the other hand, if the analysis unit 13 determines that no such virtual reactant exists (NO in step S54), the process proceeds to step S9 without executing the subsequent processes.

[0044] In step S55, the analysis unit 13 selects a predetermined virtual reactant from one or more virtual reactants. When processing a chemical reaction occurring between multiple reactants, the analysis unit 13 selects multiple virtual reactants corresponding to one of one or more combinations in which the interatomic distance of the reactants satisfies a predetermined condition. When processing a chemical reaction involving a single reactant, the analysis unit 13 selects one virtual reactant from one or more single virtual reactants in which the interatomic distance of the reactants satisfies a predetermined condition.

[0045] As described above, in step S4, one target reaction formula or multiple target reaction formulas may be acquired. In one example, the analysis unit 13 may change the process of selecting a predetermined virtual reactant depending on the number of acquired target reaction formulas.

[0046] First, an example of the process of selecting virtual reactants when multiple target reaction formulas are acquired in step S4 will be described. In one example, the analysis unit 13 selects one target reaction formula based on the relationship between the number of virtual reactants corresponding to a certain target reaction formula that exist in the reaction system and whose interatomic distances satisfy a predetermined condition and the activation energy of the chemical reaction represented by the target reaction formula. In this example, the analysis unit 13 may set a weight w for each of the multiple target reaction formulas based on the number of virtual reactants that satisfy the predetermined condition and the activation energy, and select one target reaction formula based on the weight w. The weight w may be expressed, for example, by the following equation (1):

number

[0047] Then, the analysis unit 13 selects a predetermined virtual reactant from one or more virtual reactants corresponding to the selected target reaction formula. The analysis unit 13 may randomly select the predetermined virtual reactant. Alternatively, the analysis unit 13 may select the virtual reactant based on the distance between reacting atoms. In this case, the analysis unit 13 may select, from the one or more virtual reactants, the virtual reactant with the smallest distance between reacting atoms, or a combination of virtual reactants with the smallest distance between reacting atoms.

[0048] Next, an example of the process of selecting a virtual reactant when one target reaction formula is acquired in step S4 will be described. In this case, the analysis unit 13 selects a predetermined virtual reactant from one or more virtual reactants corresponding to the one target reaction formula. As in the case when multiple target reaction formulas are acquired in step S4, the analysis unit 13 may select the predetermined virtual reactant randomly or based on the distance between reacting atoms.

[0049] In step S56, the analysis unit 13 replaces the selected virtual reactant with a virtual product. That is, the analysis unit 13 replaces one virtual reactant or one combination of virtual reactants whose interatomic distance satisfies a predetermined condition with a virtual product. In one example, the analysis unit 13 converts the selected virtual reactant into a virtual product corresponding to the product shown in the target reaction formula.

[0050] Here, an example of the process of replacing a selected virtual reactant with a virtual product will be described with reference to FIG. 6. FIG. 6 is a diagram showing an example of a reaction formula, specifically a target reaction formula showing a chemical reaction for obtaining product 600 from reactant 400 and reactant 500. In this example, the chemical reaction shown in the target reaction formula is a chemical reaction that occurs between two types of reactants, and this chemical reaction produces one type of product from the two types of reactants. That is, in the replacement process in this example, one combination is selected from combinations of one or more virtual reactants, and that combination is replaced with a virtual product.

[0051] In the example shown in FIG. 6 , reactant 400 includes reactive site 401 and residual site 402, and reactant 500 includes reactive site 501 and residual site 502. In this example, reactive site 401 is ethylene oxide, reactive site 501 is an amino group, and residual site 402 and residual site 502 are any alkyl groups. Here, residual site 402 and residual site 502 may have the same structure or different structures. Product 600 includes site 601, residual site 402, and residual site 502. Site 601 is a site formed by bonding ethylene oxide (reactive site 401) and an amino group (reactive site 501). In step S55, if a combination of virtual reactants corresponding to such a target reaction formula is selected, analysis unit 13 replaces the combination with a virtual product corresponding to product 600. In other words, this process can be said to result in a new placement of a virtual product obtained from the selected virtual reactant in the reaction system, in place of the selected virtual reactant.

[0052] In step S57, the analysis unit 13 performs structural optimization within the reaction system after the substitution. In the present disclosure, structural optimization refers to a process of setting the structures of the virtual reactants and virtual products within the reaction system so that their energy states are minimized. A structure with a minimum energy state is also referred to as a stable structure, and the analysis unit 13 can be said to set a stable structure for each of the virtual reactants and virtual products. In one example, the analysis unit 13 fixes the atomic arrangement of the replaced virtual product, excluding the site formed by the bonding of reactive sites and the atoms directly bonded to the site, and then performs structural optimization. In the example shown in FIG. 6, the analysis unit 13 fixes the atomic arrangement of the site, excluding the site 601 and the atoms directly bonded to the site 601, and then performs structural optimization.

[0053] In step S58, the analysis unit 13 executes molecular dynamics calculations for a predetermined time in the optimized reaction system. The analysis unit 13 may execute the molecular dynamics calculations for a time until the optimized reaction system reaches a stable state, or may execute the calculations for a time set by the user.

[0054] Returning to FIG. 3, in step S6, the analysis unit 13 calculates the energy of the reaction system after the substitution process. In one example, the energy is expressed as the sum of the free energy before and after the substitution process and the heat of formation when a product is obtained. The free energy is an index that indicates the difference between the energy that attempts to maintain a certain state and the energy that attempts to change that state. In other words, the free energy before and after the substitution process can be said to indicate the difference between the energy that attempts to maintain a state in which no chemical reaction shown in the target reaction formula has occurred and the energy that attempts to cause a chemical reaction.

[0055] In step S7, the analysis unit 13 determines whether the calculated energy satisfies a predetermined condition. The predetermined condition is set, for example, based on the magnitude of the calculated energy. In one example, the analysis unit 13 determines whether the calculated energy satisfies a termination condition based on whether the calculated energy is a positive value or a negative value. In this example, the analysis unit 13 determines that the calculated energy satisfies the predetermined condition if the calculated energy is zero or a negative value, and determines that the calculated energy does not satisfy the predetermined condition if the calculated energy is a positive value.

[0056] If the calculated energy is a positive value, the analysis unit 13 sets a further condition and determines whether the calculated energy satisfies the further condition. In one example, the further condition may be set based on the relationship between a random number in the range of 0 to 1 and an index i based on the magnitude of the calculated energy. The index i may be expressed by the following equation (2).

number

[0057] In this example, the analysis unit 13 determines that the specified condition is met if the index i is greater than the random number, and determines that the specified condition is not met if the index i is smaller than the random number or if the index i and the random number are the same.

[0058] If the analysis unit 13 determines that the calculated energy does not satisfy the predetermined condition (NO in step S7), the process proceeds to step S8. That is, the analysis unit 13 repeatedly executes the substitution process and calculates the energy of the reaction system each time the substitution process is executed. Then, the analysis unit 13 ends the repetition based on the calculated energy. If the analysis unit 13 determines that the calculated energy satisfies the predetermined condition (YES in step S7), the process proceeds to step S9.

[0059] In step S8, the analysis unit 13 replaces the virtual product with a virtual reactant. In one example, the analysis unit 13 replaces the virtual product with the virtual reactant selected in step S55. That is, in step S8, the analysis unit 13 returns the reaction system to the state before the replacement process was performed.

[0060] In step S9, the analysis unit 13 determines whether a termination condition is satisfied. The termination condition may be that the molecular dynamics calculation has been performed a predetermined number of times. Alternatively, the termination condition may be that the energy calculated in step S6 has been determined to not satisfy the predetermined condition a predetermined number of times in succession. If the analysis unit 13 determines that the termination condition is not satisfied (NO in step S9), the process returns to step S5. That is, the analysis unit 13 repeatedly executes a series of processes, including the replacement process, the energy calculation, and the determination of the calculated energy, until the termination condition is satisfied. If the analysis unit 13 determines that the termination condition is satisfied (YES in step S9), the process proceeds to step S10.

[0061] In step S10, the output unit 14 outputs the processing results. In one example, the output unit 14 outputs a three-dimensional graphic image showing the reaction system at the time step S9 is completed as the processing result. A user of the analysis system 10 can understand the structure of the product in the reaction system by referring to the graphic image. Alternatively, the output unit 14 may convert the virtual product into a product and output a graphic image showing the reaction system after the substitution as the processing result. The output unit 14 may output at least one of the target reaction formula and the energy of the reaction system corresponding to the graphic image together with the graphic image as the processing result. The output unit 14 may display the processing result on a display device, store the processing result in a given storage device such as a memory, or transmit the processing result to another computer system.

[0062] [Variations] Various examples of the present disclosure have been described above in detail. However, the present disclosure is not limited to the above examples. Various modifications can be made to the present disclosure without departing from the spirit and scope of the present disclosure.

[0063] If it is determined in step S54 that no virtual reactant exists whose interatomic distance satisfies the predetermined condition, the analysis unit 13 may execute the molecular dynamics calculation (step S52) and the calculation of the interatomic distance (step S53) again, rather than proceeding to step S9. That is, the analysis unit 13 may repeatedly execute a series of processes, including the execution of the molecular dynamics calculation and the calculation of the interatomic distance. In this example, the analysis unit 13 may determine whether or not there exists one or more virtual reactants whose calculated interatomic distances satisfy the predetermined condition, each time the series of processes is executed. Then, the series of processes is executed a predetermined number of times, and if it is determined each time that no such virtual reactant exists, the analysis unit 13 may terminate the process. The predetermined number of times may be input by a user operation, for example.

[0064] In step S55, the analysis unit 13 may select multiple combinations of virtual reactants or multiple virtual reactants from the multiple virtual reactants. In this example, the analysis unit 13 may select multiple combinations of virtual reactants or multiple virtual reactants by performing the same process as in the case of selecting one combination of virtual reactants or one virtual reactant. That is, the analysis unit 13 may randomly select multiple combinations of virtual reactants or multiple virtual reactants, or may select multiple combinations of virtual reactants or multiple virtual reactants based on the distance between reacting atoms.

[0065] The analysis unit 13 may execute the process of step S52 without executing the process of step S51. That is, the analysis unit 13 may execute the molecular dynamics calculation based on one or more types of virtual reactants in the reaction system without setting constraints on the one or more types of virtual reactants in the reaction system.

[0066] In relation to steps S6 and S7, the analysis unit 13 may determine whether to repeat the substitution process (step S5) based on an index other than the energy of the reaction system after the substitution process. For example, the analysis unit 13 may repeat the substitution process for a predetermined calculation time. Alternatively, the analysis unit 13 may perform the substitution process only once.

[0067] In this disclosure, the expression "at least one processor executes a first process, executes a second process, ... executes an nth process" or a corresponding expression is a concept that includes cases where the entity executing the n processes from the first process to the nth process (i.e., the processor) changes midway through. In other words, this expression is a concept that includes both cases where all n processes are executed by the same processor and cases where the processor changes among the n processes according to an arbitrary policy.

[0068] The analysis method executed by at least one processor is not limited to the above examples. For example, some of the steps or processes described above may be omitted, or the steps may be executed in a different order. Furthermore, any two or more of the steps described above may be combined, or some of the steps may be modified or deleted. Alternatively, other steps may be executed in addition to the steps described above.

[0069] [Note] As can be seen from the various examples above, the present disclosure includes the following aspects. <Item 1> at least one processor; at least one processor; the at least one processor: obtaining one or more types of reactants, each of the one or more types of reactants comprising a plurality of carbon atoms and one or more hydrogen atoms, and for each of the one or more types of reactants, the one or more hydrogen atoms comprised in the reactant comprise one or more hydrogen atoms bonded to a carbon atom of the reactant; converting each reactant into a virtual reactant in which the carbon atom and the hydrogen atom bonded to each other are combined into one virtual atom; generating a reaction system in which one or more virtual reactants are arranged for each of one or more types of virtual reactants; obtaining a target reaction formula for obtaining a product from the one or more types of reactants; a molecular dynamics calculation based on the one or more types of virtual reactants in the reaction system, and a substitution process for replacing the one or more virtual reactants that are estimated to cause a chemical reaction represented by the target reaction formula with virtual products; Analysis system. <Item 2> each of the one or more types of virtual reactants includes a reactive atom; The at least one processor, in the replacement process, calculating the distance between the reacting atoms; replacing the one or more virtual reactants, the distance of which satisfies a predetermined condition, with the virtual product; Item 1. The analysis system according to item 1. <Item 3> the one or more hydrogen atoms contained in the reactant further include one or more hydrogen atoms bonded to a heteroatom of the reactant; The at least one processor, in the replacement process, setting constraints for the one or more virtual reactants in the reaction system that fix the distance between the bonded heteroatoms and the bonded hydrogen atoms; performing the molecular dynamics calculation under the constraints; 3. The analysis system according to claim 1 or 2. <Item 4> the at least one processor: Repeating the replacement process; Calculating the energy of the reaction system each time the substitution process is performed; terminating the iteration of the substitution process based on the energy. The analysis system according to any one of items 1 to 3. <Item 5> the at least one processor refers to a database storing a plurality of reaction formulas, and acquires, from the plurality of reaction formulas, a reaction formula corresponding to the one or more types of virtual reactants disposed in the reaction system as the target reaction formula; The analysis system according to any one of items 1 to 4. <Item 6> 1. An analysis method performed by an analysis system comprising at least one processor, comprising: obtaining one or more types of reactants, each of the one or more types of reactants comprising a plurality of carbon atoms and one or more hydrogen atoms, and for each of the one or more types of reactants, the one or more hydrogen atoms comprise one or more hydrogen atoms bonded to a carbon atom of the reactant; converting each reactant into a virtual reactant in which the carbon atoms and the hydrogen atoms bonded to each other are combined into one virtual atom; generating a reaction system in which one or more virtual reactants are arranged for each of one or more types of virtual reactants; obtaining a target reaction formula for obtaining a product from the one or more types of reactants; a step of performing a molecular dynamics calculation based on the one or more types of virtual reactants in the reaction system, and performing a substitution process of replacing the one or more virtual reactants that are estimated to cause a chemical reaction represented by the target reaction formula with virtual products; Analysis methods including. <Item 7> obtaining one or more types of reactants, each of the one or more types of reactants comprising a plurality of carbon atoms and one or more hydrogen atoms, and for each of the one or more types of reactants, the one or more hydrogen atoms comprise one or more hydrogen atoms bonded to a carbon atom of the reactant; converting each reactant into a virtual reactant in which the carbon atoms and the hydrogen atoms bonded to each other are combined into one virtual atom; generating a reaction system in which one or more virtual reactants are arranged for each of one or more types of virtual reactants; obtaining a target reaction formula for obtaining a product from the one or more types of reactants; a step of performing a molecular dynamics calculation based on the one or more types of virtual reactants in the reaction system, and performing a substitution process of replacing the one or more virtual reactants that are estimated to cause a chemical reaction represented by the target reaction formula with virtual products; An analysis program that causes a computer to execute the above.

[0070] In items 1, 6, and 7, each of one or more types of reactants is converted into a virtual reactant consisting of a bonded hydrogen atom and a carbon atom. Then, through a substitution process using molecular dynamics calculations, one or more virtual reactants are replaced with virtual products. By simplifying the reactant structures in this way and then performing the substitution process using molecular dynamics calculations, the time required for molecular dynamics calculations can be shortened compared to when the substitution process is performed while taking into account the structure of each reactant as is. Therefore, the structure of the product obtained from one or more types of reactants can be predicted more quickly.

[0071] According to Item 2, in the substitution process, virtual reactants whose inter-reactant distances satisfy a predetermined condition are substituted with products. To induce a chemical reaction between multiple reactants, either heterogeneous or homogeneous, or to create new bonds within a single reactant, the reactant atoms must approach each other to a certain distance. On the other hand, to cleave existing bonds within a single reactant, the reactant atoms must be separated by a certain distance. Therefore, by setting a predetermined condition for the inter-reactant distance when substituting virtual reactants with virtual products, it is possible to accurately identify which virtual reactants will undergo a chemical reaction.

[0072] According to Item 3, a constraint that fixes the distance between the bonded heteroatoms and hydrogen atoms is set for one or more types of virtual reactants, and then a molecular dynamics calculation is performed. By setting such a constraint, it is possible to perform a molecular dynamics calculation without considering changes in the distance between the bonded heteroatoms and hydrogen atoms during the chemical reaction process. As a result, the time required for the molecular dynamics calculation can be further shortened, and the structure of the product can be predicted even faster.

[0073] According to Item 4, the substitution process is repeatedly performed, and the repetition is terminated based on the energy of the reaction system after the substitution process. For example, depending on the arrangement of one or more types of virtual reactants in the reaction system, even if the substitution process is performed normally, the energy state of the reaction system after the substitution process may become a state that cannot physically occur. In contrast, by terminating the repetition of the substitution process based on the energy of the reaction system after the substitution process, it is possible to prevent the process from ending in such a state that cannot physically occur.

[0074] According to Item 5, a reaction formula corresponding to one or more types of virtual reactants placed in a reaction system is obtained as a target reaction formula from a database that stores multiple reaction formulas. In this way, by referring to the database, a series of processes for generating a reaction system and obtaining a target reaction formula can be automatically executed without requiring a user to input the target reaction formula itself. [Explanation of symbols]

[0075] 10...analysis system, 11...acquisition unit, 12...generation unit, 13...analysis unit, 14...output unit.

Claims

1. at least one processor; the at least one processor: obtaining one or more types of reactants, wherein each of the one or more types of reactants comprises a plurality of carbon atoms and one or more hydrogen atoms, and for each of the one or more types of reactants, the one or more hydrogen atoms comprised in the reactant comprise one or more hydrogen atoms bonded to a carbon atom of the reactant; converting each reactant into a virtual reactant in which the carbon atom and the hydrogen atom bonded to each other are combined into one virtual atom; generating a reaction system in which one or more virtual reactants are arranged for each of one or more types of virtual reactants; obtaining a target reaction formula for obtaining a product from the one or more types of reactants; performing a molecular dynamics calculation based on the one or more types of virtual reactants in the reaction system, and performing a substitution process to replace the one or more virtual reactants that are estimated to cause a chemical reaction represented by the target reaction formula with virtual products; Analysis system.

2. each of the one or more types of virtual reactants includes a reactant atom; The at least one processor, in the replacement process, calculating the distance between the reacting atoms; replacing the one or more virtual reactants, the distance of which satisfies a predetermined condition, with the virtual product; The analysis system according to claim 1 .

3. the one or more hydrogen atoms contained in the reactant further include one or more hydrogen atoms bonded to a heteroatom of the reactant; The at least one processor, in the replacement process, setting constraints for the one or more types of virtual reactants in the reaction system that fix the distance between the bonded heteroatoms and the bonded hydrogen atoms; performing the molecular dynamics calculation under the constraints; The analysis system according to claim 1 or 2.

4. the at least one processor: Repeating the replacement process; Calculating the energy of the reaction system each time the substitution process is performed; terminating the iteration of the substitution process based on the energy. The analysis system according to claim 1 or 2.

5. the at least one processor refers to a database storing a plurality of reaction formulas, and acquires, from the plurality of reaction formulas, a reaction formula corresponding to the one or more types of virtual reactants disposed in the reaction system as the target reaction formula; The analysis system according to claim 1 or 2.

6. 1. An analysis method performed by an analysis system comprising at least one processor, comprising: obtaining one or more types of reactants, each of the one or more types of reactants comprising a plurality of carbon atoms and one or more hydrogen atoms, and for each of the one or more types of reactants, the one or more hydrogen atoms included in the reactant comprise one or more hydrogen atoms bonded to a carbon atom of the reactant; converting each reactant into a virtual reactant in which the carbon atoms and the hydrogen atoms bonded to each other are combined into one virtual atom; generating a reaction system in which one or more virtual reactants are arranged for each of one or more types of virtual reactants; obtaining a target reaction formula for obtaining a product from the one or more types of reactants; a step of performing a molecular dynamics calculation based on the one or more types of virtual reactants in the reaction system, and performing a substitution process of replacing the one or more virtual reactants that are estimated to cause a chemical reaction represented by the target reaction formula with virtual products; Analysis methods including.

7. obtaining one or more types of reactants, each of the one or more types of reactants comprising a plurality of carbon atoms and one or more hydrogen atoms, and for each of the one or more types of reactants, the one or more hydrogen atoms included in the reactant comprise one or more hydrogen atoms bonded to a carbon atom of the reactant; converting each reactant into a virtual reactant in which the carbon atoms and the hydrogen atoms bonded to each other are combined into one virtual atom; generating a reaction system in which one or more virtual reactants are arranged for each of one or more types of virtual reactants; obtaining a target reaction formula for obtaining a product from the one or more types of reactants; a step of performing a molecular dynamics calculation based on the one or more types of virtual reactants in the reaction system, and performing a substitution process of replacing the one or more virtual reactants that are estimated to cause a chemical reaction represented by the target reaction formula with virtual products; An analysis program that causes a computer to execute the above.

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