memory 20 GB molecule dimer { 1 1 Na 3.55507100 9.74889100 12.49176200 -- -4 1 Si 3.48578100 6.60211800 13.81562200 S 2.07667300 7.56341700 12.44597000 S 4.39445500 8.14220400 14.79926900 S 4.93265100 5.48271900 12.60076600 S 1.90492800 5.40855500 14.87579700 } set { scf_type DF freeze_core True basis jun-cc-pVDZ } energy('sapt0')