Isotopic effects in accidental predissociation. The case of the C2Σ+u state of N+2

✍ Scribed by A.J. Lorquet; J.C. Lorquet

• Publisher: Elsevier Science
• Year: 1974
• Tongue: English
• Weight: 534 KB
• Volume: 26
• Category: Article
• ISSN: 0009-2614
• DOI: 10.1016/0009-2614(74)89104-9

✦ Synopsis

The large isotopic effect recently found in the decay of the C 'Cc state of Nf is interpreted by an indirect (accidental) predissociation mechanism. The C *X; state interacts with a bound intermediate state, itself predissociated by a repulsive state. The competition between fluorescence and predissociation is controlled by the energy difference separating adjacent levels of the two bound states. This energy difference will be different for each vibrational level of each isotope. Ruorescence and predissociation rate constants are given for each level, and the position of the intermediate bound state is titted to a Morse potential_ Recently; Govers et al. [7] reported that the competition between these two channels is subject to a very large and unexpected isotopic effect: the ratio of the predissociation and fluorescence rate constants for a particular vibrational level varies a great deal when comparing the 14N14Nf, 14N15N+ and 15N15N+ isotopes and factors of five to ten were found for nearly all vibrational levels. In an extended paper on the subject, van de Runstraat et al. [8] argued that the interpretation of such an effect in terms of a direct pre-