High-Resolution Infrared Study of the nu14, nu17, and nu18 Bands of 11B2H6 and 10B11BH6.
Using high-resolution Fourier transform spectra, a thorough analysis of the nu14 c-type, nu17 a-type, and nu18 a-type bands of both 11B2H6 and 10B11BH6 has been carried in the 10.3-, 6.2-, and 8.5-µm spectral regions, respectively. From this analysis a large set of precise ground state combination differences with J values up to 36 (31) and Ka values extending to 18 (18) was derived for 11B2H6(10B11BH6). These data were fitted using a Watson-type Hamiltonian leading to accurate ground state rotational constants. An rs value for the B-B distance has been determined to be 1.7645(10) Å. The determination of upper state Hamiltonian constants proved to be much more difficult since the corresponding rotational levels of each of the bands are strongly perturbed by nearby dark states. To account for these strong localized resonances, it was necessary to introduce the relevant interacting terms in the Hamiltonian matrix. As a result it was possible to calculate the upper state energy levels quite satisfactorily. From these fits, estimates of the band centers and a few of the rotational constants of the resonating dark states were obtained. Copyright 1998 Academic Press.
Sams
RL
Pacific Northwest National Laboratory, Battelle Boulevard, Richland, Washington, 99352
Blake
TA
Sharpe
SW
Flaud
J
Lafferty
WJ