Recent developments towards time-resolved electron diffraction at York

摘要: The ability to observe directly the dynamics of molecules is extremely desirable in our attempts to better understand structurefunction relationships. In order to achieve experimental dynamics, a direct method of probing molecules with sub-picosecond time resolution is needed. Work performed by Ahmed Zewail and others has already demonstrated the use of diffraction to probe the ultrafast dynamics of molecules, 1 with many early experiments relying on X-rays generated by synchrotron sources in order to produce the required beam brightness and time resolution. 2, 3 This reliance on expensive X-rays sources can be overcome by the use of a more manageable diffraction probe: electrons. Electrons have a larger scattering cross section, are less damaging to molecular samples, and are more easily controlled than X-rays. And thanks to the recent developments in ultrafast pulsed lasers, as well as the commercial availability of femtosecond laser sources, electrons can now be produced using “table-top” apparatus. Therefore, time-resolved electron diffraction (TRED) experiments have become a relatively cheap alternative to the use of synchrotron facilities, empowering university-based research groups to study the dynamics of molecules with atomic resolution.