ISSN:
1089-7690
Source:
AIP Digital Archive
Topics:
Physics
,
Chemistry and Pharmacology
Notes:
The fluctuating charge (FQ) model proposed by Rick et al. [(J. Chem. Phys. 101, 6141 (1994)] for molecular dynamics (MD) simulation of water is applied to a test case for polyatomic ionic systems. A system resembling alkali cyanide crystals, with two partial charges on the atomic sites of the polarizable anions, is considered. The need for charge fluctuation considerations in such a simple system is demonstrated by ab initio calculations of the partial charges in the cyanide ion with different orientations within a fixed octahedral environment of sodium ions. It is shown that the charge distributions in the crystal obtained with the FQ model are sensitive to changes in the environment in such a way that the anions become more polarizable as the lattice parameter increases. Conversely, the charge distributions shrink with increasing repulsive short-range interactions. Furthermore, a well-known polarization effect, that is, the reduction in the frequencies of longitudinal optic modes of the crystal, is also obtained with the FQ model. © 1999 American Institute of Physics.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1063/1.479085
Permalink