The BaI X-2 Sigma(+) and B-2 Sigma(+) electronic states through B-2 Sigma(+)-X-2 Sigma(+) and (CII)-I-2-X-2 Sigma(+) band systems analysis

The near-infrared spectrum of the B(2)Sigma(+) - X(2)Sigma(+) band system o f the Pal molecule, obtained from the chemiluminescent reaction Ba + I-2 an d also by laser-induced fluorescence (LIF), was recorded by using Fourier t ransform spectroscopy (FTS). The LIF spectra were obtained by using a Ti:sa pphire single-mode laser excitation. Resolved rotational data, originating from 32 vibrational levels (0 less than or equal to v less than or equal to 31) in the X(2)Sigma(+) state and from 24 vibrational levels (0 less than or equal to v less than or equal to 19, and v = 21, 22, 23, 26) in the B(2) Sigma(+) state, were used in the final analysis. Previously recorded data f or the C(2)Pi - X(2)Sigma(+) band system (with Delta v = 0), taken from C. A. Leach, A. A. Tsekouras, and R. N. Zare, J. Mol. Spectrosc. 153, 59-72 (1 992), were added to the present work data field. Accurate and improved mole cular constants for the X(2)Sigma(+), B(2)Sigma(+), and C(2)Pi states were derived from a simultaneous treatment of the whole data set. (C) 1999 Acade mic Press.