title: Cryogenic terahertz spectrum of (+)-methamphetamine hydrochloride and assignment using solid-state density functional theory.
abstract: The cryogenic terahertz spectrum of (+)-methamphetamine hydrochloride from 10.0 to 100.0 cm(-1) is presented, as is the complete structural analysis and vibrational assignment of the compound using solid-state density functional theory. This cryogenic investigation reveals multiple spectral features that were not previously reported in room-temperature terahertz studies of the title compound. Modeling of the compound employed eight density functionals utilizing both solid-state and isolated-molecule methods. The results clearly indicate the necessity of solid-state simulations for the accurate assignment of solid-state THz spectra. Assignment of the observed spectral features to specific atomic motions is based on the BP density functional, which provided the best-fit solid-state simulation of the experimental spectrum. The seven experimental spectral features are the result of thirteen infrared-active vibrational modes predicted at a BP/DNP level of theory with more than 90% of the total spectral intensity associated with external crystal vibrations.
authors.affiliation: Department of Chemistry, Syracuse University, Syracuse, New York 13244-4100, USA.
authors.forename: Patrick M
authors.initials: PM
authors.lastname: Hakey
authors.forename: Damian G
authors.initials: DG
authors.lastname: Allis
authors.forename: Wayne
authors.initials: W
authors.lastname: Ouellette
authors.forename: Timothy M
authors.initials: TM
authors.lastname: Korter