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Title: Diode laser studies of collisional energy transfer

Journal Article · · Journal of Physical Chemistry; (United States)
DOI:https://doi.org/10.1021/j100133a003· OSTI ID:6072684
 [1];  [2]
  1. Columbia Univ., New York, NY (United States)
  2. Brookhaven National Lab., Upton, NY (United States)

Time-resolved infrared diode laser absorption spectroscopy has proven to be a remarkably sensitive probe for the study of collisional energy transfer processes. The high spectral resolution makes it possible to determine the rovibrational states, as well as the translational energy content, of small molecules excited in collisions. We illustrate this technique with studies of [open quotes]hot[close quotes] atom collisions and show that in the case of H + CO[sub 2] encounters the experimental results can be explained by a simple [open quotes]breathing ellipsoid[close quotes] model. Recently, we applied diode laser spectroscopy to studies of collisional energy transfer from highly vibrationally excited molecules, containing chemically interesting amounts of energy. Our results indicate that most of the energy loss from the donor molecule results in rotational and translational, rather than vibrational, excitation of the [open quotes]bath[close quotes] gas species. The small number of collision events which lead to vibrational excitation of the bath molecule states appears to be dominated by long-range forces in which donor vibrational energy is exchanged for acceptor vibrational energy with little or no excitation of the rotational and translational degrees of freedom. 127 refs., 10 figs., 3 tabs.

DOE Contract Number:
FG02-88ER13937; AC02-76CH00016
OSTI ID:
6072684
Journal Information:
Journal of Physical Chemistry; (United States), Vol. 97:31; ISSN 0022-3654
Country of Publication:
United States
Language:
English