The potential energy surfaces for AlO2 using multi-reference wave functions

We report a systematic multi-configurational study of several low lying states of AlO2 in a wide region of the coordinate space, in order to provide additional insight into the electronic structure of the AlO2 molecule. This work attempts to resolve the question of the global minimum energy structure for the AlO2 molecule. A symmetry breaking observed in the vicinity of the linear geometry at the multi-configurational self-consistent field (CASSCF) level of theory is shown to be due to insufficient accounting of dynamic correlation, since it does not appear in multi-reference configuration interaction (MRCI) or multi-reference perturbation theory calculations (MCQDPT).