psi4.set_memory('8GB') psi4.core.set_num_threads(12) molecule oxygen_dimer { 0 3 O 0.00000000 0.00000000 2.62151500 O 0.00000000 0.00000000 1.37848500 -- 0 3 O 0.43947747 0.00000000 5.48947747 O -0.43947747 0.00000000 4.61052253 } set basis aug-cc-pVTZ E = energy('MP2',molecule=oxygen_dimer, bsse_type='cp') Efinal = E* psi_hartree2kcalmol psi4.print_out("MP2/aug-cc-pVTZ = ") psi4.print_out("%10.6f" % (Efinal))