Deperturbation Analysis of the [18.5]1-X0+ System and the Electronic Structure of ReN: A Laser Induced and Dispersed Fluorescence Study

Abstract

We report a deperturbation analysis of the [18.5]1-X0+ system of ReN. Heterogeneous Ja uncoupling involving a “dark” (Ω = 2) state is responsible for the observed perturbation. For the (0−0) band located near 540 nm, extra branches as well as an irregular energy level pattern are observed. For the (1−0) band near 510 nm, although the observed spectrum appears regular, the B‘ value deduced from a previous analysis is not consistent with values associated with other vibrational levels. A careful reexamination of this band, using dispersed fluorescence to filter the laser induced fluorescence (LIF) spectra, allowed us to separate the “bright” and “dark” state contributions to the original LIF spectrum. In fact two spectra can be obtained, corresponding mainly either to the “bright” or to the “dark” excited states. Rotational analyses have been carried out for both of these (1−0) bands and confirm the deperturbation analysis of the (0−0) bands. Excited state lifetimes have been measured for individual ro-vibr...