INFRARED INTENSITY AS A SPECTRAL SIGNATURE OF H-BOND FORMATION IN SMALL AMMONIA CLUSTERS STUDIED IN HE DROPLETS
Loading...
Date
2006
Journal Title
Journal ISSN
Volume Title
Publisher
Ohio State University
Abstract
Infrared spectra and intensities of the $\nu_1$, $\nu_3$ H-stretching modes of (NH$_3$)$_n$ clusters (n = 2-4) have been obtained using the helium droplet isolation technique. Formation of a hydrogen bond in ammonia dimers leads to an increase of the infrared intensity by about a factor of four. In the larger clusters the infrared intensity per bond is close to that of dimers and approaches the value in the NH3 crystal. Intensity of the overtone 2$\nu_4$ band in trimers increases by a factor of 10 relative to that in single molecules and in dimers, and is comparable to the intensity of the $\nu_1$, $\nu_3$ fundamental bands in larger clusters. These results provide new insights into the hydrogen bonding in ammonia clusters.
Description
Author Institution: 1605 Gilman Hall, Department of Chemistry, Iowa State University, Ames, IA 50011-3111; on leave from: General Physics Institute, Russian Academy of Sciences, Moscow, 119991,; Russia; Department of Chemistry, University of Southern California, Los Angeles, CA 90089, USA