HIGH-RESOLUTION FOURIER-TRANSFORM EMISSION-SPECTROSCOPY OF THE A(6)SIGMA(-X(6)SIGMA(+) SYSTEM OF CRD())

using a Fourier transform spectrometer. The CrD molecules were formed in a chromium hollow cathode lamp operated with neon gas and a trace o f deuterium. Compared with the previous work on this molecule the pres ent spectra provide greatly improved measurements of line positions an d allow the analysis of several new bands. The rotational analysis of the 0-1, 0-0, 1-0, and 1-2 bands has been performed providing the foll owing principal molecular constants for the ground X(6) Sigma(+) state : omega e = 1183.1958(21) cm(-1), omega(e)x(e) = 15.6006(9) cm(-1), B- e = 3.175443(21) cm(-1), and r(e) = 1.654730(5) Angstrom. The excited A(6) Sigma(+) state, with principal constants T-00 = 11559.7206(6) cm( -1), Delta G(1/2) = 1066.4202(10) cm(-1), B-e = 2.762705(13) cm(-1), a nd r(e) = 1.774034(4) Angstrom, is involved in several perturbations. The observed perturbations in the upsilon = 0 and upsilon = 1 vibratio nal levels are similar to those observed previously in the upsilon = 0 vibrational level of the A(6) Sigma(+) state of CrH. These perturbati ons arise from interactions with a nearby a(4) Sigma(+) state with pre liminary molecular constants: T-00 = 11 176 cm(-1), B-e = 3.19 cm(-1). This state located below the A(6) Sigma(+) state and is the lowest ex cited state of this molecule, supporting the conclusions of our previo us work on CrH. (C) 1995 Academic Press, Inc.