Electronic states of the hafnium trimer (Hf3)

The equilibrium geometries and bending potential energy surfaces of twelve electronic states of the hafnium trimer (Hf3) are obtained by the complete active space multi-configuration self-consistent field (CAS-MCSCF) followed by multi-reference configuration interaction computations (MRSDCI) that included up to 2.23 million configurations. The spin–orbit effects were found to be quite significant. We reassign the recently observed spectra of Hf3 to arise from an A1 spin–orbit state of 3A2.