TITLE:

Analysis of BaI C²Ð - X²Ó⁺ (0,0) band for high rotational levels

AUTHORS:

Zhao, D.; Vaccaro, P.H.; Tsekouras, A.A.; Leach, C.A.; Zare, R.N.; Dept. of Chem., Stanford Univ., CA, USA

PUBLICATION:

Journal of Molecular Spectroscopy, vol.148, no.1, p. 226-42, July 1991 15 Refs.

ABSTRACT:

Using laser-induced fluorescence, rotationally resolved spectra of the BaI C²Ð - X²Ó⁺ (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 X²Ó⁺ 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".