Combined CI–HY studies of atomic states. II. Compact wave functions for the be ground state

Combined CI – HY method techniques have been employed in obtaining a 57‐term CI – HY wave function with an energy of −14.66632 a.u. A method due to Brown has been adopted for obtaining this wave function and various shorter expansions. A 44‐term expansion with an energy of −14.66606 a.u. is analyzed in terms of various pair effects, and qualitative arguments are presented for understanding these effects.