Microwave Spectrum of BrCN and Dependence of Quadrupole Coupling Constant on the Vibrational State

Abstract

The hyperfine structure of the J=1←0 and J=2←1 rotational transitions of BrCN has been measured. The values of eqQ(Br⁷⁹) and eqQ(Br⁸¹) for each vibrational state were obtained as follows.
(Remark: Graphics omitted.)
Considerable increase of eqQ for the stretching vibration (v₁=1) is explained in terms of the decrease of the double bond character of Br–C bond, and the decrease of eqQ for the excitation of the bending vibration (v₂=1) is ascribed to the variation of the z component of q tensor.