Analysis of BaI C2 - X2+ (0,0) band for high rotational levels
Zhao, D.; Vaccaro, P.H.; Tsekouras, A.A.; Leach, C.A.; Zare, R.N.; Dept. of Chem., Stanford Univ., CA, USA
Journal of Molecular Spectroscopy, vol.148, no.1, p. 226-42, July 1991 15 Refs.
Using laser-induced fluorescence, rotationally resolved spectra of the BaI C2 - X2+ (0,0) band have been observed for J" values from 339.5 to 486.5 in the P12, 57.5 to 494.5 in the P2, and 124.5 to 370.5 in the R21 branches. The BaI molecules are formed from the reaction of Ba and HI. These new data have been combined with lower J" lines (J"<156.5) previously measured by Johnson, Noda, McKillop, and Zare (Can. J. Phys. 62, p.1467-1477 (1984)). All the high J" lines have been unambiguously assigned, although lines in the P12 branch between J" values of 156.5 and 338.5 have not been observed. A rotational analysis has been carried out by performing a nonlinear least-squares fit to the eigenvalue differences of the model Hamiltonians for the upper and lower states. In addition, a further least-squares fit was carried out including all the (0,0) band data and the six X2+ v=0 microwave rotational transitions of Torring and Dobl (Chem. Phys. Lett. 115, p.328-332 (1985)). Six out of the twelve rotational branches form blue-shaded bandheads at J" well over 400. These bandheads are caused by the difference between the centrifugal distortion constants D' and D".