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J. Phys. Chem. A 2010, 114, 4364–4374
Terahertz Spectroscopic Investigation of S-(+)-Ketamine Hydrochloride and Vibrational Assignment by Density Functional Theory Patrick M. Hakey, Damian G. Allis, Matthew R. Hudson, Wayne Ouellette, and Timothy M. Korter* Department of Chemistry, Syracuse UniVersity, Syracuse, New York 13244-4100 ReceiVed: NoVember 16, 2009; ReVised Manuscript ReceiVed: January 16, 2010
The terahertz (THz) spectrum of (S)-(+)-ketamine hydrochloride has been investigated from 10 to 100 cm-1 (0.3-3.0 THz) at both liquid-nitrogen (78 K) and room (294 K) temperatures. Complete solid-state density functional theory structural analyses and normal-mode analyses are performed using a single hybrid density functional (B3LYP) and three generalized gradient approximation density functionals (BLYP, PBE, PW91). An assignment of the eight features present in the well-resolved cryogenic spectrum is provided based upon solid-state predictions at a PW91/6-31G(d,p) level of theory. The simulations predict that a total of 13 infraredactive vibrational modes contribute to the THz spectrum with 26.4% of the spectral intensity originating from external lattice vibrations. I. Introduction The analytical applications of terahertz (THz, far-infrared,
