Ab initio calculations on low-lying electronic states of TeO₂and Franck-Condon simulation of the (1)¹B₂←X̃¹A₂TeO₂absorption spectrum including anharmonicity

The state-of-the-art ab inito calculations and reliable Franck-Condon simulations were carried out to understand the low-lying electronic states of TeO2and its observed laser induced fluorescence (LIF) spectrum. The harmonic vibrational frequencies, equilibrium geometrical parameters, and relative electronic energies of the low-lying singlet and triplet states of TeO2were calculated. The ab inito results and spectral simulation confirmed the upper electronic state involved in the LIF spectrum to be the1B2state of TeO2. The spectral simulation suggests that the reported LIF spectrum is only part of the full absorption spectrum.