University:
Widener University
Course:
PHYS-121 | Fundamentals of Physics I
Academic year:

2023
Views:

368

Pages:

1
Author:

kerkstoelm66

Lecture # 34 Supplement Contents 1. 1. “Intramolecular Radiationless Transitions” by M. Bixon and J. Jortner . . . . . . . . . . . . . . . . . 1 “Intramolecular Radiationless Transitions” by M. Bixon and J. Jortner J. Chem. Phys. 48, 715-726 (1967). ABSTRACT In this paper we consider a theory for intramolecular radiationless transi tions in an isolated molecule. The Born-Oppenheimer zero-order excited states are not pure in view of conﬁguration interaction between nearly degenerate zero-order states, leading to the broadening of the excited state, the line shape being Lorentzian. The optically excited state can be described in terms of a superposition of molecular eigenstates, and the resulting wavefunction exhibits an exponential nonradiative decay. The linewidth and the radiationless lifetime are expressed in terms of a single molecular parameter, that is the square of the interaction energy between the zero-order state and the manifold of all vibronic states located within one energy unit around that state. The validity criteria for the occurrence of an unimolecular radiationless transition and for exponential decay in an isolated molecule are derived. Provided that the density of vibra tional states is large enough (i.e., exceeds the reciprocal of the interaction matrix element) radiationless transitions are expected to take place. The gross eﬀects of molecular structure on the relevant molecular parameters are discussed. 1