Very low temperature helium pressure broadening of DCl in a collisionally cooled cell

Abstract

Very low temperature pressure broadening parameters and cross sections for the J=0-1 rotational transition of DCl broadened by helium are presented. Data was taken using a collisionally cooled cell and measured cross sections range from 10.76 Å2 at 4.21 K to 8.10 Å2 at 1.85 K. This compares with a 300 K cross section of 9.36 Å2. Predictions from two currently available anisotropic He-DCl potentials do not reproduce accurately the experimental results. Modifications were made to one of these potentials to reproduce more accurately both the observed low temperature and 300 K pressure broadening cross sections. The resulting modified potential has a well depth De = 32.7 cm-1 at a separation R e = 3.46 Å in the linear He-Cl-D configuration. © 1992 American Institute of Physics.