Thermodynamic and radiative properties of TiO in local thermal equilibrium and non-equilibrium conditions

Abstract

The thermodynamic and radiative properties of TiO in the local thermodynamic equilibrium (LTE) and non-LTE (NLTE) were investigated. Firstly, we investigated the potential energy curves of fifteen electronic states of TiO by the icMRCI + Q method with a large aug-cc-pwCV5Z-DK basis set. Then the internal partition functions, average internal energies, specific heats at temperatures from 100 to 15,000 K in the LTE and NLTE were obtained. The contributions of different states are not affected by the condition of the gas. In addition, the transition dipole moments for eight transitions and the radiative properties (absorption and emissivity) of TiO in the LTE and NLTE were obtained. The A3Φ−X3Δ, B3Π−X3Δ and C3Δ−X3Δ transitions play a key role in the calculations of the absorption and emissivity. The absorption and emissivity in the LTE and NLTE were also calculated, and the electronic and vibrational energy highly contributes to the absorption and the translational and rotational energy highly contributes to the emissivity.