Anomalous isotope effects in indirect predissociations An example in the spectrum of BeH
Abstract
Measurements of the linewidths in the (3 pπ) B2Π state of BeH and BeD which is predissociated by a 2Σ + state show an anomalous isotope effect. Ab initio calculations of the five lowest excited 2Σ + states of BeH show that the first excited 2Σ + state is stable at a large inter-nuclear distance and is responsible for the observed predissociation. The anomalous isotope effect is explained by an indirect mechanism of predissociation involving this 2Σ + state and the (3 pσ) 2Σ + state which is separated from the (3 pπ) B2Π state by an energy of the order of magnitude of ωe. A new method to calculate the widths and the shifts of predissociated levels is presented and calculations in the case of BeH and BeD give good agreement with the experimental data.
- Publication:
-
Journal of Molecular Spectroscopy
- Pub Date:
- April 1977
- DOI:
- 10.1016/0022-2852(77)90356-3
- Bibcode:
- 1977JMoSp..65...33L