Core-State Excitation Using Two-Color X-Rays for Active Center Cancellation
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Solution Overview
Problem
Current technologies face challenges in selectively cancelling the effect of the active center of target molecules, such as those in pathogens, without affecting identical surrounding molecules.
Innovation Solution
The method involves illuminating a target molecule with two synchronized ultrashort intense X-ray pulses of different central photon energies, using a laser, to selectively excite core states of the target molecule and surrounding molecules through resonantly-enhanced difference-frequency generation (re-DFG) effect.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If resonant excitation near a core atomic ionization edge is used to achieve selective photodissociation of target molecules, then the biochemical function of the active center is cancelled, but the molecule becomes unstable and dissociates which may affect surrounding identical molecules
Solution Approach 1:
The invention divides the excitation process into two distinct steps: first creating a transient grating with one X-ray pulse, then probing with a second pulse. This temporal segmentation allows selective excitation of the target molecule's active center without causing immediate dissociation that would affect surrounding molecules, as the excitation is confined to the spatial and temporal overlap region of the two pulses.
Solution Approach 2:
The method uses two synchronized ultrashort X-ray pulses with a controlled time delay between them, creating a periodic excitation pattern. The first pulse creates the transient grating, and the second pulse probes it after a specific delay, allowing selective core state excitation while controlling the dissociation timing to minimize impact on surrounding molecules.
2Measurement precision
If two-color X-ray pulses with different central photon energies are used to achieve resonantly-enhanced difference-frequency generation, then core states are selectively excited, but the process requires synchronized intense pulses which increases device complexity
Solution Approach 1:
The invention uses an optical transient grating as an intermediary between the two X-ray pulses. The first X-ray pulse creates a spatial modulation in the sample, and the second X-ray pulse reads this modulation. The optical field acts as a mediator that enables the difference-frequency generation process while providing a clear temporal and spatial separation that simplifies synchronization requirements compared to direct two-color X-ray mixing.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach allows for highly selective core excitation of target and surrounding molecules, potentially disrupting the biochemical functions of pathogens while minimizing impact on surrounding molecules.
Implementation Method 1
illuminating a target molecule with two synchronized ultrashort intense X-ray pulses using a laser, the two synchronized ultrashort intense X-ray pulses having different central photon energies (i.e. two-color) the subtraction of which matches the photon energy of a peak of the core spectrum of the target molecule, such that a core state of an atom of the target molecule, and also of identical surrounding molecules, is selectively excited by the re-DFG effect
Implementation Method 2
recent advances in the development of intense ultrashort X-ray coherent pulse sources, such as synchrotron, free-electron lasers (FEL) and in high-harmonic generation
Data Source
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AI summary
A method and an apparatus for selectively cancelling the effect of the active center of a molecule are provided. The method comprises illuminating a target molecule with two synchronized ultrashort X-ray pulses using a laser, the two synchronized ultrashort X-ray pulses having different central photon energies the subtraction of which matches the photon energy of a peak of the core spectrum of the target molecule, such that a core state of an atom of the target molecule, and also of identical surrounding molecules, is selectively excited by the re-DFG effect as a result of the illumination. The method is implementable for simple or complex molecular systems and bulk materials.