Lawrence Berkeley National Laboratory

The nitrogen K-edge Near Edge X-ray Absorption Fine Structure (NEXAFS) spectrum of alpha-crystalline glycine has been calculated for temperatures ranging from 0 K to 450 K. Significant temperature dependent spectral changes are predicted. The calculated room temperature spectrum is in good agreement with experiment. At high temperatures, molecular motions strongly influence the spectrum, as any unique spectrum from an individual instantaneous configuration does not resemble the experimental result or the average calculated spectrum; complex coupled motions in this prototypical molecular crystal underlie the observed spectral changes.