Three-dimensional quantum theory of the H + H2 transition-state spectrum

T. Seideman*, M. Shapiro

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

17 Scopus citations


Three-dimensional quantal transition-state spectra due to optical transition between the reactive H + H2 system on the ground electronic surface and the lowest excited H3 Rydberg state are computed. The computations are based on a three-dimensional (3D) extension of the reactive-WKB [J. Chem. Phys. 88, 5525 (1988)] method, which is also shown to be a reliable tool for studying reactive processes in the tunneling regime. The three-dimensional quantum transition-state spectrum is found to be substantially different from both its classical 3D and its quantum-collinear analogs. Due to the prominence of high partial waves for most transitions, the quantum undulations which reflect in the collinear domain the initial scattering states, are masked (save for the far red end of the spectrum) by the rotational line contours. The latter are shown to reflect the quantum oscillations of the final bound vibrational states in the excited electronic state. The role of the stretching vs bending overlaps in determining the band shapes is discussed. Contrary to ordinary linear-to-bend spectra, the greater latitude for bending motion in the initial scattering states results in only a moderate progression of bending states. The possibility of extracting individual partial scattering amplitudes and the use of transition-state spectroscopy as a first step in a laser catalysis scheme is discussed.

Original languageEnglish (US)
Pages (from-to)2328-2341
Number of pages14
JournalThe Journal of Chemical Physics
Issue number4
StatePublished - Jan 1 1990

ASJC Scopus subject areas

  • Physics and Astronomy(all)
  • Physical and Theoretical Chemistry


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