Imaging rotations and vibrations in polyatomic molecules with X-ray scattering

Abstract

An approach for calculating elastic X-ray scattering from polyatomic molecules in specific electronic, vibrational, and rotational states is presented, and is used to consider the characterization of specific states in polyatomic molecules using elastic X-ray scattering. Instead of the standard independent atom model (IAM) method, the X-ray scattering is calculated directly from ab initio wavefunctions. The role of molecular symmetry and Friedel's law is examined, with the molecules BF₃, C₅H₅^-, NF₃, and 1,3-cyclohexadiene used as specific examples. The contributions to the elastic X-ray scattering from the electronic, vibrational, and rotational portions of the molecular wavefunction are examined in CS₂. In particular, it is observed that the rotational states give rise to distinct signatures in the scattering signal.