CAS SCF/CI calculations of potential energy surfaces of He 3+ and He 2+

Abstract

Complete active space MC SCF (CAS SCF) calculations followed by second-order configuration interaction (SOCI) calculations are carried out on the potential energy surfaces (bending surface, linear surfaces) of the 2Σ g + ground state of He 3 +. The potential minimum for the 2Σ g + state occurs at a linear geometry with HeHe bond length of 1.248 Å. The binding energy of He 3 + with respect to He + He + + He was calculated to be 2.47 eV at the SOCI level. The energy required to dissociate He 3 + ( 2Σ g +) into He 2 + ( 2Σ u +) and He( 1S) is calculated to be 0.14 eV. The same level of SOCI calculations of He 2 + yield a D e value of 2.36 eV.