COMPARISON OF LOW TEMPERATURE PRESSURE BROADENING OF $NH_{3}$ BY HE, NORMAL- $H_{2}$ AND PARA-$H_{2}$
Date
2001
Journal Title
Journal ISSN
Volume Title
Publisher
Ohio State University
Abstract
We have completed low temperature pressure broadening studies of $NH_{3}$ inversions transitions for broadening by He and molecular hydrogen. Pressure broadening of the $(J,K) = (1, 1), (2, 2)$ and (3, 3) inversion transitions of $NH_{3}$ by He, normal- $H_{2}$ and para- $H_{2}$ has been observed from 10 to 40 K. We find that the He cross sections are the smallest followed by the para- $H_{2}$ cross sections which are two to five times larger with the normal- $H_{2}$ cross sections being two to ten times larger than for He. In addition, we have used ab initio potential surfaces to calculate He and para- $H_{2}$ cross sections for comparison with our experimental data.
Description
Author Institution: Allegheny College; Department of Physics, Allegheny College