title: 2D calculation of anharmonic OH vibrations in a layered hydroxide crystal.
abstract: Anharmonic vibrational frequencies for the Raman-active (A(1g)) and the IR-active (A(2u)) modes have been calculated for the LiOH crystal within a plane-wave density functional theory (DFT) framework. We find that a two-dimensional quantum-mechanical vibrational approach, allowing for anharmonic coupling between symmetric and antisymmetric OH stretching modes, produces OH frequencies--both absolute frequencies and gas-to-solid frequency shifts--in good agreement with experiment. Remaining errors in the absolute frequencies are largely a consequence of the DFT model chosen. A one-dimensional normal-mode following vibrational treatment, on the other hand, fails to reproduce both absolute anharmonic frequencies and gas-to-solid frequency shifts.
authors: Materials Chemistry, The Angstrom Laboratory, Uppsala University, Box 538, S-75121 Uppsala, Sweden.
authors: Grzegorz
authors: G
authors: Gajewski
authors: Pavlin D
authors: PD
authors: Mitev
authors: Kersti
authors: K
authors: Hermansson