Detection of Radiation Damage in Organic Crystals

Abstract

In X-ray diffraction experiments with single crystals, the loss in intensity of Bragg reflections caused by radiation damage can become more severe at higher scattering angle, similar to the effect of increased thermal motion or disorder. Long exposure to X rays can also lead to an increase in the lattice dimensions, similar to the effect of thermal expansion. Both effects are illustrated by observations with 4,5, 10, ll-tetraoxa-I, 2, 7, 8-tetraazatricyc10[6.4.1. 12,7]tetradecane made in connection with a charge density study of this molecule. Recommendations are made for the choice of standard reflections and measurement strategies for accurate crystal structure analysis of radiation sensitive compounds.