The H2S Spectrum around 0.7 µm

[In Process Citation]

A novel model for the analysis of the rovibrational structure of a molecule based on anharmonic ladder operators associated with the vibrational degrees of freedom is presented. This is devised as an alternative method for the global spectral analysis of rovibrational data considering vibrational anharmonicities from the outset. The present method is thought up with an effective rovibrational Hamiltonian written in terms of angular momentum components and anharmonic Morse ladder operators, associated with rotational and vibrational degrees of freedom, respectively. The resulting Hamiltonian is diagonalized in a symmetry-adapted basis set expressed as a product of rotational states and individual 1D-Morse wave functions for each local vibrational degree of freedom. This approach has been successfully applied to the study of the vibrational structure (up to polyad 14) and the rovibrational structure (up to polyad 2 and J(max) = 20) of hydrogen sulfide. It was shown that this new global analysis formalism is able to reduce considerably the number of fitted parameters with respect to the spectral analysis carried out for separate polyads.

The Overtone Spectrum of H2 32S near 13 200 cm-1

The intracavity laser absorption spectrum of H2 32S has been recorded near 13 200 cm-1 with an equivalent absorption pathlength of 25 km. The observed spectrum is assigned to the (50(+/-), v2 = 1) states constituting a local mode pair in strong H22-type interaction. The rovibrational analysis has allowed the assignment of 210 lines involving 86 rotational upper state levels which have been reproduced with a rms of 0.023 cm-1 close to the experimental accuracy. A perturbation affecting one line is assigned to a local interaction with the (40(+/-), v2 = 3) local mode pair. The influence of the bending excitation on the local mode character of the (n0(+/-), v2 = 1) stretch-bend combination levels is discussed on the basis of the values of the rotational constants and of the H22 interaction parameters. Copyright 1999 Academic Press.