Visible Spectrum of Titanium Dioxide

The electronic spectrum in the region 17 500 cm−1 to 18 850 cm−1 of a cold molecular beam of TiO2 has been investigated using laser induced fluorescence (LIF) and mass-resolved resonance enhanced multi-photoionization (REMPI) spectroscopy. Bands at 18 412 cm−1, 18 470 cm−1 and 18 655 cm−1 were recorded at a resolution of 35 MHz, rotationally analyzed, and assigned as the Ã1B2 (0,1,2) ← [X with combining tilde]1A1 (0,0,0), Ã1B2 (1,0,0) ← [X with combining tilde]1A1 (0,0,0) and Ã1B2 (1,1,0) ← [X with combining tilde]1A1 (0,0,0) transitions. The dispersed fluorescence from the Ã1B2 (0,1,2) and Ã1B2 (1,0,0) levels were combined with previous results to produce an improved set of vibrational parameters for the [X with combining tilde]1A1 state. The optical Stark effect in the Ã1B2 (0,1,2) ← [X with combining tilde]1A1 (0,0,0) and Ã1B2 (1,0,0) ← [X with combining tilde]1A1 (0,0,0) bands were recorded and combined with earlier results for Ã1B2 (1,1,0) ← [X with combining tilde]1A1 (0,0,0) to determine the permanent electric dipole moment for these states. The origin and harmonic vibrational constants for the Ã1B2 state are determined to be: T000 = 17 593(5) cm−1, ω1 = 876(3) cm−1, ω2 = 184(1) cm−1, and ω3 = 316(2) cm−1. A normal coordinate analysis was performed and Franck–Condon factors calculated.