Fermi resonance and mode specificity in the vibrational autoionization of NO{sub 2}
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907 (United States)
Ionization-detected absorption spectra of autoionizing Rydberg series converging to the (100), (010), (02{sup 0}0), and (02{sup 2}0) vibrational states of NO{sup +}{sub 2} have been recorded using three-color triple resonant excitation. Resonances produced by relaxation of the core, excited in one quantum of the bending vibration, (010), are found to be much sharper than those associated with decay by relaxation in symmetric stretch, (100), consistent with earlier findings on mode specificity of vibrational autoionization in this system. In contrast, series excited in the symmetric overtone of the bend, (02{sup 0}0), are found to exhibit dynamics that resemble much more those of series built on one quantum of symmetric stretch, indicating that the bending specificity that characterizes (010) is lost in the overtone. This loss of mode specificity with increasing vibrational energy is ascribed to moderate (100){endash}(02{sup 0}0) Fermi resonance in the NO{sup +}{sub 2} core, exemplifying how even small vibrational coupling can affect mode-specific pathways in polyatomic molecules. {copyright} {ital 1996 American Institute of Physics.}
- DOE Contract Number:
- FG02-93ER14401
- OSTI ID:
- 253450
- Journal Information:
- Journal of Chemical Physics, Journal Name: Journal of Chemical Physics Journal Issue: 1 Vol. 104; ISSN JCPSA6; ISSN 0021-9606
- Country of Publication:
- United States
- Language:
- English
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