Ab initio study on the hydrogen bonding complex between hydrogen sulfide and ammonia by means of configuration analysis

Abstract

The intermolecular interaction and electronic and vibrational structures of the H 2S··NH 3 hydrogen bonding systme are investigated by performing the electronic configuration analysis and vibrational analysis on the basis of ab initio SCF MO method. It is confirmed that the present system forms a loosely bound complex with non-linear SH··N hydrogen bonds in the gas phase. The electronic delocalization due to the charge transfer from NH 3 to H 2S and the polarization due to the local excitation on H 2S are found to play essential roles in the stabilization of the present system and also the new H··N hydrogen bond formation. Vibrational analysis reveals that the normal vibrations of NH 3 deforming, SH stretching, and HSH bending modes exhibit notable frequency shifts enough to show a trend of vibrational changes associated with the hydrogen bond formation. These representative vibrations are discussed from the viewpoint of electron—molecular vibration interaction by correlation with electronic configurations derived from the configuration analysis.