An accurate isotopically invariant potential function of the hydrogen sulphide molecule

The potential function of the electronic ground state of the hydrogen sulph ide molecule is obtained by the simultaneous fit of a very large sample of high-resolution vibration-rotation data. The use of an extensive set of mor e than 12000 experimental rovibrational transitions, corresponding to 4175 rovibrational states with J(max) = 15, K-a max = 15 for bands of 7 isotopom ers ((H2S)-S-32, (H2S)-S-33, (H2S)-S-34, (D2S)-S-32, (D2S)-S-34, (HDS)-S-32 , and (HDS)-S-34), allows improved calculations of 'local-mode states' and highly excited bending-rotational states. The root-mean-square (PMS) deviat ion of the rovibrational fit is 0.05 cm(-1). For the entire set of all 73 b and centres of all isotopic species for which experimental data exists, the RMS deviation of the results of calculations with a single isotopic invari ant potential function is 0.03 cm(-1). (C) 2001 Elsevier Science B.V. All r ights reserved.