... basis "ao basis" * library 6-311+g* bqN library N 6-311+g* bqH library H 6-311+g* bqO library O 6-311+g* bqC library C 6-311+g* end scf direct maxiter 999 end mp2 freeze atomic end bsse mon first 1 2 mon second 3 4 end task mp2 energy