Visible spectrum of titanium dioxide

Abstract

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 ùB₂ (0,1,2) ← ¹A₁ (0,0,0), ùB₂ (1,0,0) ← ¹A₁ (0,0,0) and ùB₂ (1,1,0) ← ¹A₁ (0,0,0) transitions. The dispersed fluorescence from the ùB₂ (0,1,2) and ùB₂ (1,0,0) levels were combined with previous results to produce an improved set of vibrational parameters for the ¹A₁ state. The optical Stark effect in the ùB₂ (0,1,2) ← ¹A₁ (0,0,0) and ùB₂ (1,0,0) ← ¹A₁ (0,0,0) bands were recorded and combined with earlier results for ùB₂ (1,1,0) ← ¹A₁ (0,0,0) to determine the permanent electric dipole moment for these states. The origin and harmonic vibrational constants for the ùB₂ 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.