Dipole matrix elements for vibration–rotation lines in the fundamental band of the hydrogen bromide molecule

Abstract

The equivalent widths of 16 lines in the fundamental vibration–rotation band of the H⁷⁹Br molecule are measured in the linear region of the curve-of-growth method. The measurements are made on a Littrow type high-resolution infrared grating spectrometer in a double-pass manner so that the two isotopic lines of H⁷⁹Br and H⁸¹Br, which are separated by approximately 0.4 cm⁻¹, could be completely resolved. From the measurements of equivalent widths, the strengths and squares of the dipole matrix elements for the spectral lines are calculated. This is the first time the high-resolution work on the fundamental band has ever been presented. The present high-resolution values are found to be approximately one-half of the values of an earlier low-resolution work.