Knowledge Bank

Spectra of natural hydrogen sulfide have been recorded between 2150 and $2950cm-1$ on a Bomem spectrophotometer with a resolution of $0.010cm-1$. The careful analysis of the $2\nu 2,\nu 1$ and $\nu 3$ bands of the three species $H232S,H233S$ and $H234S$ has led to a complete and precise set of rotational energy levels of the three vibrational interacting states (020), (100) and (001) for the three isotopes. Then using these data we have been able to determine the rotational and coupling constants involved in the upper-states Hamiltonian. About 530 line intensities of $H232S$ were measured from which precise transition moments of the 3 bands under study were derived leading to the determination of the first derivatives of the dipole moment with respect to the normal coordinates $q1$ and $q3$. Besides it is to be pointed out that the strong intensity anomalies appearing in the $\nu 3$ band are well reproduced by the calculation. Finally the complete spectrum of natural hydrogen sulfide has been computed.