Stimulated Raman excitation of the {ital ortho}-H{sub 2}{endash}OH entrance channel complex
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323 (United States)
The fundamental H{sub 2} vibration of the {ital ortho}-H{sub 2}{endash}OH complex in its ground electronic state has been observed at 4151.49{plus_minus}0.03&hthinsp;cm{sup {minus}1} via stimulated Raman excitation. The stimulated Raman transition has been identified with an ultraviolet probe laser using two different detection schemes. The transition was detected as a depletion in the H{sub 2}{endash}OH laser-induced fluorescence signal in the OH A&hthinsp;{sup 2}{Sigma}{sup +}{endash}X&hthinsp;{sup 2}{Pi} (1,0) spectral region and through the appearance of OH A&hthinsp;{sup 2}{Sigma}{sup +}{endash}X&hthinsp;{sup 2}{Pi} (0,1) laser-induced fluorescence following vibrational predissociation of the complex. Vibrational predissociation is found to proceed via a near-resonant pathway that transfers one quantum of vibrational excitation from H{sub 2} to OH. The remaining {approximately}529 cm{sup {minus}1} of available energy is distributed over excited rotational states of OH (v=1) and the lowest rotational level of {ital ortho}-H{sub 2} (v=1), with the balance flowing into translational recoil. The lifetime of vibrationally activated {ital ortho}-H{sub 2}{endash}OH ({nu}{sub H{sub 2}}=1) is determined to be less than 7 ns, the temporal resolution of the lasers, by monitoring the time evolution of the OH products. The results are compared with previous infrared studies of OH vibrational activation in {ital ortho}-H{sub 2}{endash}OH as well as full collision studies of the reaction of vibrationally excited H{sub 2} with OH. {copyright} {ital 1999 American Institute of Physics.}
- OSTI ID:
- 341163
- Journal Information:
- Journal of Chemical Physics, Journal Name: Journal of Chemical Physics Journal Issue: 14 Vol. 110; ISSN JCPSA6; ISSN 0021-9606
- Country of Publication:
- United States
- Language:
- English
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