15min:

ILIA J. KALINOVSKI, X. L. CHEN, WAI Y. FAN, C. BRADLEY MOORE, Chemical Sciences Division of the Lawrence Berkeley National Laboratory and Department of Chemistry of UC Berkeley, California 94720 and Department of Chemistry, The Ohio State University, 120 W. 18th Avenue, Columbus, Ohio 43210.

Laser-induced fluorescence spectroscopy of the A²A₁ X²E transition of asymmetrically deuterated methoxy radicals, CHD₂O and CH₂DO, has been studied. From the origin of the A²A₁ state to 4100 cm^-1 above it, 75 fluorescence excitation bands that involve modes ₂, ₃, '₅, ''₅, '₆, ''₆ and their combinations have been observed and assigned for CHD₂O. Harmonic frequencies, diagonal and off-diagonal anharmonicities have been determined for most of the modes of A²A' CHD₂O. A smaller set of bands has been recorded and vibrations assigned for CH₂DO. Ten vibrational bands of CHD₂O and six of the CH₂DO are rotationally analyzed. An effective rotational Hamiltonian is proposed for the ground state, which combines the spin-orbit interaction with a special effective term that is attributable to the removal of the X² E vibronic degeneracy induced by the aymmetric deuteration. The LIF results provide a selection of intermediate states to choose from for our ongoing Stimulated Emission Pumping and fluorescence depletion spectroscopy work that is a prelude to studying the state-selective unimolecular reaction dynamics of the electronic ground state of methoxy.