LASER AND FOURIER-TRANSFORM SPECTROSCOPY OF THE [23.8]1-X-0(+) SYSTEM OF REN

The emission spectrum of ReN has been observed in the 400-476 nm spectral region using a Fourier transform spectrometer. The bands were excited in a rhenium hollow cathode lamp in the presence of a trace of N-2. The observed bands, with the 0-0 band at 23 746.42 cm(-1), have been assigned as the [23.8] 1-X0(+) electronic transition. A rotational analysis of the 0-1, 0-0, and 1-0 bands for both (ReN)-Re-187 and (ReN)-Re-185 isotopomers has been performed. The principal ground state equilibrium molecular constants for (ReN)-Re-187 obtained from this analysis are B-e('') = 0.482414(11) cm(-1), r(e)('') = 1.63780(2) Angstrom, while the corresponding excited state values are B-e(') = 0.441093(13) cm(-1), r(e)(') = 1.71280(3) Angstrom. The 0-0 band was also observed by pulsed dye laser excitation spectroscopy using a free jet expansion source. In this experiment, the ReN was made by laser vaporization of a rhenium rod followed by reaction with NH3. The excited [23.8] 1 state has a fluorescence lifetime of 201 +/- 1 nsec. There are no previously reported observations of the ReN molecule. (C) 1994 Academic Press, Inc.