Knowledge Bank

The $\nu 2$ band of $H2S$ exhibits remarkably large intensity perturbations due to centrifugal distortion. A previous low resolution study of this $band1$ found that the P branch is about 1/5 as intense as the R branch. In this work, the strengths of 94 lines in the $\nu 2$ band have been measured to an average accuracy of 3% using a tunable diode laser. Since the observed low pressure line widths are on the average only 1.3% larger than the calculated Poppler widths, the line profile distortion is small, and thus the strengths could be determined using the line center absorption with slight corrections to account for residual line broadening by the laser bandwidth and gas pressure. The maximum values of J, $Ka$, and $Ke$ observed are 12, 7, and 10 respectively. The measured line strengths range from 5 times larger to 17 times smaller than strengths calculated using a Watson-type Hamiltonian with an untransformed dipole moment operator.