IR spectrum of highly vibrationally excited OsO sub 4 in the region of strong nonlinear interaction of vibrational modes

The authors measured a linear infrared absorption spectrum (the {nu}{sub 3} band, {nu}{sub L} = 884-955 cm{sup {minus}1}) of OsO{sub 4} prepared at the high-lying vibrational states of E{sub vib} = 33,000 {plus minus} 250 cm{sup {minus}1} through radiationless transition. Contrary to the {nu}{sub 3} transition from the ground state, the experimental spectrum manifests features of strong nonlinear interaction between the {nu}{sub 3} stretching and {nu}{sub 2}, {nu}{sub 4} bending modes. A suggested theoretical model explains general characteristics of the spectrum obtained.