REMPI spectra of Cl2; Vibrational and rotational analysis of the 2 1Pg Rydberg states of 35Cl2, 35Cl37Cl and 37Cl2.

Gísli Hólmar Jóhannesson, Huasheng Wang and Ágúst Kvaran
Science Institute, University of Iceland, Dunhaga 3, 107 ReykjavÌk, Iceland

Abstract

Rotational contours of the (2+1) resonance enhanced multiphoton ionization (REMPI) spectra of the vibrational bands corresponding to the 2 1Pg <- X transitions in 35Cl2, 35Cl37Cl and 37Cl2 for the natural abundance of isotopes have been recorded at room temperature. Vibrational bands consist of contributions from all three isotopomers with varying degrees of overlap depending on vibrational quantum numbers. Band heads and tails were analyzed by simulation calculation. Rotational constants (B and D) and corresponding internuclear distances (r) for the Rydberg state were obtained, as well as equilibrium position rotational parameters. Thus for 35Cl2, Be´= 0.2763±0.0008 cm-1, ae´= 0.0015±0.0001 cm-1 and re´= 1.868±0.005 Å. Vibrational analysis based on the detemination of band origins from the spectral simulations were performed to obtain we´= 664.8±0.2 cm-1, wexe= 2.62±0.02 cm-1 for 35Cl2, and Te´= 63970±3 cm-1. Spectroscopic parameters for 35Cl37Cl and 37Cl2 are derived from the ones for 35Cl2 in a standard way (see text).