2006 Fiscal Year Final Research Report Summary
Time-resolved X-ray diffractometry of organic crystals by using synchrotron radiation
| Project/Area Number |
16072218
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| Research Category |
Grant-in-Aid for Scientific Research on Priority Areas
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| Allocation Type | Single-year Grants |
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| Review Section |
Science and Engineering
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| Research Institution | The Institute of Physical and Chemical Research |
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Principal Investigator |
TANAKA Yoshihito The Institute of Physical and Chemical Research, Coherent X-ray Optics Lab., Senior Research Scientist (80260222)
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| Project Period (FY) |
2004 – 2006
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| Keywords | Time-resolved X・ray diffraction / Organic crystal / Synchrotron radiation / Photochromic crystal / Lattice dynamics |
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| Research Abstract |
We have developed fast time-resolved X-ray diffraction system at the SPring-8 synchrotron radiation facility. The lattice response of a photochromic single crystal induced by pulsed laser irradiation has been investigated using the time-resolved measurement system. The details of the obtained results on the demonstration of picosecond time-resolved diffractometry for semiconductor crystals (1) and the observation of lattice response of a diarhylethene single crystal (2) are described below.
(1). Time-resolved X-ray diffraction measurement system with multi-channel scaling (MCS) and pump-probe method using the pulsed time-structure of synchrotron radiation has been developed. Triple crystal X-ray diffractometry (TCD) has been applied to the time-resolved measurement system to determine the lattice response along a specific axis in distinction from the other components of deformation. In the time-resolved TCD, a monochromatic X-ray beam is diffracted by a crystal sample, and the angle of
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the diffracted beam is analyzed using the additional single crystal before detection. We have demonstrated the time-resolved TCD to detect acoustic pulses and the echoes as dynamical lattice strain at semiconductor crystals of silicon and gallium arsenide.
(2). A photochromic crystal of diarhylethene turns blue by UV light irradiation, and is recovered to be original colorless crystal by visible light illumination. The time-evolution of the diffraction intensity has successfully been measured with the MCS by changing the color with alternate irradiation by the lasers of 400 nm and 633 nm. The results showed that the crystal expands during irradiation, and that the shear strain or local rotation as well as dilational change is kept after cooled-down at the interval of irradiations. In combination with space-resolved X-ray diffraction measurement method using an X-ray slit of 50 μm-width, local strain with a response time of a few μs has been observed around the surface on the illumination side. Less
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