title: Theoretical calculation of structures and proton transfer in hydrated ammonia-hydrogen chloride clusters.
abstract: Ab initio molecular orbital calculations have been performed to investigate the structures and quantum effects of the proton motion in NH(3):HCl:(H(2)O)(n) (n = 0-3) clusters using a MP2/aug-cc-pVDZ level of theory. Three new stable structures and one transition-state structure are investigated for these clusters. The detailed analyses of the intermolecular interactions suggest that three-body interactions play an important role to determine the relative stability in each size of cluster. The quantum effects of the proton motion result in frequency shifts for proton-stretching modes. Our one-dimensional and two-dimensional models fairly closely reproduce the experimental proton-stretching vibrational frequency of the NH(3):HCl cluster. The most stable isomer for n = 1 has a proton-transfer structure, which is weakened by the quantum effects of the proton motion.
authors.affiliation: Department of Chemistry, Osaka Prefecture University, 1-1 Gakuen-cho, Sakai-city, Osaka 599-8531, Japan. asada@ms.cias.osakafu-u.ac.jp
authors.forename: Toshio
authors.initials: T
authors.lastname: Asada
authors.forename: Seisuke
authors.initials: S
authors.lastname: Takitani
authors.forename: Shiro
authors.initials: S
authors.lastname: Koseki