A quantum-mechanical method for calculating level widths and shifts, applicable to type I unimolecular predissociation

Abstract

A quantum mechanical approach to type I unimolecular predissociation is developed in terms of Feshbach's optical potential. The resulting method is formally applicable to many cases of molecular breakup caused by the crossing of coupled bound and dissociative electronic surfaces. These include cases in which multiple bound and/or dissociative channels are accessible. There are two restrictions : (1) coupling among dissociative channels should be negligible, and (2) only two product fragments are allowed, of fixed atomic composition regardless of internal state. A harmonic oscillator coupled to a dissociative infinite-step or hard-sphere potential is used in comparing the usual perturbation theory results to the present approach.

This research was sponsored by the National Aeronautics and Space Administration under Grant No. NSG-2198, the Air Force Office of Scientific Research (AFSC), United States Air Force, under Contract Nos. F44620-74-C-0073 and F49620-78-C-0005, and the National Science Foundation under Grant Nos. CHE75-06775 A01 and CHE77-27826. The United States Government is authorized to reproduce and distribute reprints for governmental purposes notwithstanding any copyright notation hereon.

This research was sponsored by the National Aeronautics and Space Administration under Grant No. NSG-2198, the Air Force Office of Scientific Research (AFSC), United States Air Force, under Contract Nos. F44620-74-C-0073 and F49620-78-C-0005, and the National Science Foundation under Grant Nos. CHE75-06775 A01 and CHE77-27826. The United States Government is authorized to reproduce and distribute reprints for governmental purposes notwithstanding any copyright notation hereon.

Notes

This research was sponsored by the National Aeronautics and Space Administration under Grant No. NSG-2198, the Air Force Office of Scientific Research (AFSC), United States Air Force, under Contract Nos. F44620-74-C-0073 and F49620-78-C-0005, and the National Science Foundation under Grant Nos. CHE75-06775 A01 and CHE77-27826. The United States Government is authorized to reproduce and distribute reprints for governmental purposes notwithstanding any copyright notation hereon.

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Notes on contributors

Thomas F. George

Camille and Henry Dreyfus Teacher-Scholar Alfred P. Sloan Research Fellow.