General applicability of optical crystallography to time-resolved serial X-ray crystallography

van Thor, Jasper J

doi:10.26434/chemrxiv.15006330/v1

File(s)

chemrxiv.15006330_v1.pdf (7.31 MB)

Author(s)

van Thor, Jasper J

Type

preprint

Abstract

Femtosecond laser excitation of molecular crystals results in heterogeneous populations under all conditions of laser power, laser polarization, and crystal symmetry. Crystal optics determine the photoselection and heterogeneous distributions in time-resolved crystallography; their analysis allows the separation of pure species from the photochemical ensemble. Laser fluence dependence of timeresolved crystallography can therefore not be rigorously analyzed without accounting for the ensemble contributions. Since the separation of heterogeneous populations under a single fluence already provides an interaction dependence at the level of pure species, the additional measurement of the fluence dependence is not strictly necessary under most conditions. Optical crystallography can be applied generally to all 230 three-dimensional space groups and for all combinations of linear and circular optical polarization and linear and circular absorber types, including the photoselection treatment applicable to cubic systems. Specific guidance for all these combinations is presented, with the specific consideration of Xray crystallographic data for serial crystallography, which includes the treatment of pseudomerohedral twinning.