Theoretical ab initio study on the electronic states of GaO and Ga 2O

Abstract

Potential energy curves have been calculated for the ground and excited doublet and quartet states of the radical gallium monoxide. The ground state, X 2 Σ +, is found to have a minimum at 1.65 Å with a well-depth of 4.65 eV, while the lowest excited state, A 2Π is found to lie very close to the ground state, at ν 00 of 4204 cm −1 with r min at 1.803 Å and a well depth of 4.06 eV. The next excited state, B 2 Σ +, which is the only excited state for which there is published experimental information, is well separated from the two lower states, with a shallow minimum of 1.81 eV calculated at 1.706 Å. Non adiabatic interactions between the three lowest electronic states of GaO are weak, and there is no significant mixing of the vibrational levels of the X 2 Σ + and A 2Π caused by rotational-electronic coupling, even for very high values of the rotational quantum number N. The present calculations support the earlier reported values for the rotational constants of the X 2 Σ + and the B 2 Σ + states rather than those of the more recent findings. Symmetric stretch potentials have been calculated for electronic states of the Gallium suboxide (Ga 2O) molecule at linear geometries. The first excited state, A 1Π u, is calculated at 5.03 eV above the ground electronic state, X 1 Σ g +. The ground state and most of the excited states of Ga 2O have minima at linear geometries.