Electronic absorption spectrum of titanium dioxide in neon matrices

Anions of titanium dioxide produced by sputtering TiO2/graphite composite rods were trapped in 6 K neon matrices following mass selection. The electronic absorption spectrum of titanium dioxide has been measured subsequently, after exposing the matrices to UV radiation, revealing absorptions in the visible and UV regions. Bent and linear forms of TiO2 have been observed with absorptions in the visible range.
Two electronic systems of the bent isomer, 1B2 ← X1A1 and 1B1 ← X1A1, are observed with origins at 524 and 368 nm in agreement with theoretical calculations. The electronic transition lying at 524 nm shows a long vibronic progression due to excitations of the symmetric stretching and bending modes of TiO2. The linear form shows a transition at 628 nm for which a progression involving the symmetric stretching mode of TiO2 is apparent. The spectral assignments have been supported by analysis of the vibrational structure associated with each electronic transition.