Millimeter wave measurements of the rotational spectra of ClF, BrF, BrCl, ICl, and IBr

Publisher Website
Google Scholar
Abstract
The rotational spectra of all twelve stable isotopic species of ClF, BrF, BrCl, ICl, and IBr were observed and measured in the millimeter wave region by means of a sensitive microwave spectrometer. Transitions were detected over a wide range of frequencies for molecules in both the ground vibrational state and several excited states. The rotational spectrum of each molecule was split by the nuclear quadrupole interaction. Altogether, 250 new lines were measured. These correspond to 136 pure rotational transitions. Values of the Dunham coefficients Y01, Y11, Y21, Y31, Y02, Y12, and Y03 were obtained from a computer analysis of the measured frequencies. From these coefficients a number of equilibrium constants were derived to significantly greater accuracy than in previous work. In particular, the equilibrium distance, re, was found to two or three more significant figures.