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4 AND 2
9 BANDS OF 11BF2OH AND 10BF2OH: EVIDENCE OF LARGE AMPLITUDE EFFECTS FOR THE OH-TORSION-BENDING MODES IN THE 92 AND 41 STATES.
A. PERRIN, E. BERTSEVA, Laboratoire Inter Universitaire des Systemes Atmosphériques, CNRS, Université Paris 12, 61 Av du General de Gaulle, 94010 Créteil Cedex France; H. BÜRGER, Anorganische Chemie, FBC, Universität, D-42097 Wuppertal, Germany; J. DEMAISON, F. WILLAERT, Laboratoire PhLAM, CNRS, Université de Lille I, Bat. P5, 59655 Villeneuve d'Ascq Cedex, France; A. MASIELLO, T. A. BLAKE, Pacific Northwest National Laboratory, 902 Battelle Boulevard, P.O. Box 999, Richland, WA 99352, USA; A. MARENICH, J. E. BOGGS, Department of Chemistry, University of Texas, Austin, Texas, 78712-1167 USA.
High resolution (2-3 x 10-3 cm-1) Fourier transform infrared spectra of gas phase 11B and 10B enriched and natural samples of BF2OH (difluoroboric acid) were recorded at Wuppertal and Richland. Starting from the results of previous studies, it has been possible to perform the first rovibrational analysis of the
4 (BOH bending) and 2
9 (first overtone of
9, the OH torsional mode) bands located at 961.5 and 1042.9 cm-1) and at 961.7 and 1043.9 cm-1) for the 11BF2OH and 10BF2OH isotopic species respectively. In addition to various "classical" vibration-rotation resonances, large amplitude effects were observed for both the 2
9 and
4 bands. These result in a doubling of levels of about 0.004 and 0.003 cm-1) for the 92 and 41 states respectively. The energy level calculations account for these large amplitude torsion-bending perturbations using the IAM- type method, and for the "classical" vibration -rotation resonances.