The A 6Σ+-X 6Σ+ transition of CrH, Einstein coefficients, and an improved description of the A state

The spectrum of CrH has been reinvestigated in the 9000-15 000 cm(-1) region using the Fourier transform spectrometer of the National Solar Observatory. The 1-0 and 1-1 bands of the A (6)Sigma (+)-X (6)Sigma (+) transition have been measured and improved spectroscopic constants have been determined. A value for the 2-0 band origin has been obtained from the band head using estimated spectroscopic constants. These data provide a set of much improved equilibrium vibrational and rotational constants for the A (6)Sigma (+) state. An accurate description of the A-X transition has been obtained using a multireference configuration interaction approach. The inclusion of both scalar relativity and Cr 3s3p correlation are required to obtain a good description of both states. The ab initio computed Einstein coefficients and radiative lifetimes are reported. (C) 2001 American Institute of Physics.