A Potential Energy Surface for the Electronic Ground State of H2Te Derived from Experiment
We report here the determination of a new potential energy surface for the electronic ground state of the H2Te molecule by fitting to an extensive set of very recent experimental spectroscopic data (see J.-M. Flaud, P. Arcas, H. Burger, O. Polanz, and L. Halonen, J. Mol. Spectrosc. 183, 310-335 (1997), and references therein) by means of the MORBID (Morse Oscillator Rigid Bender Internal Dynamics) computer program. The fitting to all 1111 input data (involving rotation-vibrational states with J </= 10) had a standard deviation of 0.18 cm-1 and was obtained by varying 14 parameters. With the new potential energy function, the rotation-vibration energies of H2130Te have been calculated with the MORBID program. In particular, we have calculated the rotational energy manifolds for J </= 40 in the lowest vibrational states. Compared to previous potential energy functions for H2Te, the new function has substantially improved the reproduction of the rotational spacings in the excited vibrational states. An important aim of the present work is the further characterization of the anomalous "fourfold cluster effect" (i.e., the formation of four-member groups of nearly degenerate rotation-vibration energies at high rotational excitation) exhibited by the energy levels of H2Te. Comparison of our theoretical results with the experimental results of J.-M. Flaud, M. Betrencourt, P. Arcas, H. Burger, O. Polanz, and W. J. Lafferty (1997, J. Mol. Spectrosc. 182, 396-420) provides conclusive evidence for the existence of so-called Type II clusters (clusters formed by coalescence of two energy doublets belonging to two different vibrational states) in the nu1/nu3 vibrational states of H2130Te. Copyright 1997 Academic Press. Copyright 1997Academic Press
Gomez
PC
Facultad Quimica, U. Complutense de Madrid, Madrid, E-28040, Spain
Jensen
P