Theory for continuum resonance Raman scattering in diatomics using irreducible spherical tensors

Abstract

A theory is presented which describes resonance Raman scattering via continuum electronic states of diatomic molecules. It is applied to the dissociative continuum of the bounded B(3rI,+,)-state and the continuum of the repulsive 'HI,, state of the halogen molecules. Using spherical tensors and Wigner 3-j symbols, closed forms for the resonance Raman intensities for different polarizations are given, which allow first principle calculations for molecules for which the vibrational wavefunctions of ground and electronic excited states as well as the oscillator strengths are known from absorption of fluorescence data.

Polarized and depolarized continuum resonance Raman scattering of molecular iodine: accurate determination of repulsive states

“…Because the theory employed in this paper has been described earlier in detail (6,8), only a short summary with the essential ideas is presented here.…”

“…For the two directions of polarization, the three rotational branches, and the three intensity terms given in eq. [8] one has to calculate 18 algebraic rotational factors (6). The complex functions…”

“…Kiefer and Bemstein (2) measured the Raman spectra of iodine excited in the resonant region with high resolution and explained the various features o f the fundamental and overtone bands by means of Fortrat parabolas and the thermal distribution of the states as S-, Q-, and O-branches. Theoretical calculations were performed in order to simulate the spectra (3)(4)(5)(6)(7)(8). In the case of bromine, Baierl and Kiefer (6)(7)(8) showed that two excited electronic states, the repulsive Inlu and the bound 3no+u state, have to be taken into account in order to calculate the spectra.…”

“…Theoretical calculations were performed in order to simulate the spectra (3)(4)(5)(6)(7)(8). In the case of bromine, Baierl and Kiefer (6)(7)(8) showed that two excited electronic states, the repulsive Inlu and the bound 3no+u state, have to be taken into account in order to calculate the spectra. The influence of these two states appears in very specific band shapes and depolarization ratios of the fundamental Q-branch for excitation with different laser frequencies.…”

Quantum interference effects in the Br2 electronic predissociation: Dependence upon the molecular properties

“…The main channels for the Br 2 electronic predissociation dynamics can be represented as [ , and D 0 is the dissociation energy. The potential energy curves for the X and B states as well as the transition dipole moments between the X and B states, M XB ϭ 0.1279 a.u., and between the X and ⌸ states, M X⌸ ϭ 0.2022 a.u., are known experimentally [12]. However, the dipole moment of the B and ⌸ states (M B⌸ ) is not known and because the ⌸ state is repulsive its experimental potential energy curve is not known as accurately as the bound states.…”