First-Principles Simulation of Anharmonic and Anisotropic Vibrations of Glycinate on Copper

Abstract

Molecular vibrations within a hydrogen-bonded network are expected to be significantly anharmonic and hence poorly described by conventional normal-mode analysis. Moreover, the rather flat potential energy landscapes experienced in such cases imply sampling of several local energy minima, casting further doubt upon the standard methodology. Both difficulties may be overcome through first-principles molecular dynamics, used here to obtain vibrational spectra and thermal ellipsoids for glycinate adsorbed on copper. Vibrational anisotropy and signatures of hydrogen bonding are highlighted and discussed.