Journal of Chemical Physics, Vol.105, No.16, 6771-6777, 1996
Laser Excitation Spectroscopy of the B(1)Sigma(+)(U)(O-U(+))(-A(3)Pi(G)(O-G(+)) of Cd-2 - Vibrational Analysis and Rotational Structure
The B-1 Sigma(u)(+)<--a(3) Pi(g) transition of Cd-2 (natural abundance) and Cd-114(2) has been observed by laser excitation spectroscopy and analyzed. By exciting the Cd-2 B<--a transition in the visible (560 less than or equal to lambda less than or equal to 730 nm) while monitoring B-1 Sigma(u)(+)-->X(1) Sigma(g)(+) (bound-->free) emission in the ultraviolet (similar to 270-310 nm), more than 40 red-degraded vibrational bands were recorded, Analysis of the spectrum has yielded vibrational constants for both the a(3) Pi(g) and B-1 Sigma(u)(+) states : omega(e) "=153.6+/-4.0 cm(-1), omega(e) " x(e) "=0.52+/-0.06 cm(-1), omega(e)’=105.3+/-1.0 cm(-1) and omega(e)’x(e)’=0.44+/-0.03 cm-1. In addition, Delta R(3)=R(eB)-R(ea) was determined to be 0.31+/-0.03 Angstrom. Rotational structure has been partially resolved for Cd-114(2) bands in the 620-655 nm and 719-723 nm regions, and the spontaneous emission lifetime of the a (3) Pi(g) State and the rate constant for quenching of Cd-2 (a(3) Pi(g)) by collisions with background Cd atoms have been determined to be 8.6+/-2.5 mu s and (2.2+/-0.3)x10(-13) cm(3) s(-1), respectively. Also, analysis of the B-->X emission (Condon internal diffraction) spectra produced when specific B-1 Sigma(u)(+) vibrational levels are populated has yielded R(eX)-R(eB)=0.95+/-0.02 Angstrom.