Photodissociation spectroscopy of Li-H2O and Li-D2O complexes

The absorption spectra of Li-H2O and Li-D2O, produced by the laser vaporiza tion technique, are examined in the energy region of 10300-11700 cm(-1) usi ng a photodepletion method. Vibrationally resolved bands beginning at energ ies of 10464 and 10525 cm(-1) are observed for Li-H2O and Li-D2O, respectiv ely. These peaks are assigned to the transition from the 1(2)A(l) ground st ate to the 2(2)A(l) excited state correlating to Li(P-2) + H2O((1)A(1)). Th is transition is more than 4000 cm(-1) to the red of the Li ((2)p-S-2) atom ic transition. The extensive redshift of the 2(2)A(1)-1(2)A(1) transition i s ascribed to the large increase in ionic character in the upper state due to partial electron transfer. The spectrum of the Li-H2O complex exhibits t wo extra vibronic bands in the region of 300-500 cm(-1) above the origin. T hese bands are tentatively ascribed to the transitions as a result of vibro nic interaction between the low-lying excited states.