ELECTRONIC SPECTROSCOPY AND VIBRATIONAL PREDISSOCIATION DYNAMICS OF OH-KR AND OD-KR

OH/D-Kr complexes have been characterized via laser excitation of the A-X system. Progressions of the OH/D-Kr stretch were seen in conjunction with the OH/D 0-0 and 1-0 transitions. Rotational analyses of 17 bands provided ground state rotational constants of B" = 0.0835 (OH-Kr) and 0.0806 cm-1 (OD-Kr). These constants correspond to an intermolecular separation of 3.78 +/- 0.01 angstrom. Assignment of the A state vibrational levels was accomplished by means of the Kr-84/Kr-86 isotope effect. A lower limit for the dissociation energy of OH(A,upsilon = 0)-Kr of D(e) > 1840 cm-1 was derived from the vibrational constants. Extrapolation of the rotational constants yielded an equilibrium intermolecular separation of 2.67 +/- 0.12 angstrom. The properties defined by the spectroscopic analysis indicated weak, van der Waals bonding in the ground state, and incipient chemical bonding in the excited state. Vibrational predissociation of OH/D-Kr was observed through homogeneous broadening of the rotational lines. The predissociation rates ranged from < 1 x 10(10) to 4 x 10(11) s-1, with a general trend of decreasing decay rate with increasing excitation of the intermolecular stretch. Wavelength resolved fluorescence spectra showed that predissociation of OH-Kr partitioned approximately 40% of the available energy into OH(A,upsilon = 0) rotation. Predissociation of OD-Kr released almost-equal-equal-to 25% of the energy to OD(A,upsilon = 0) rotation.