Is SAPT2+ supported via psi4.sapt()?

jxzou · July 26, 2021, 4:42pm

I notice that there is an advanced example of SAPT calculation, via calling psi4.sapt(). However, it seems that only SAPT0 (and also sSAPT0 if reference rhf is set) is supported. Can SAPT2+, SAPT2+(3)δMP2 be supported via calling psi4.sapt()?

Thank you.

hokru · July 26, 2021, 5:05pm

That is already possible I think, at least to some extend.
You need to manually specify further options as done here automatically:

github.com

psi4/psi4/blob/master/psi4/driver/procrouting/proc.py#L4250-L4272

    
      
          if name in ['sapt0', 'ssapt0']:
              core.set_local_option('SAPT', 'SAPT_LEVEL', 'SAPT0')
          elif name == 'sapt2':
              core.set_local_option('SAPT', 'SAPT_LEVEL', 'SAPT2')
          elif name in ['sapt2+', 'sapt2+dmp2']:
              core.set_local_option('SAPT', 'SAPT_LEVEL', 'SAPT2+')
              core.set_local_option('SAPT', 'DO_CCD_DISP', False)
          elif name in ['sapt2+(3)', 'sapt2+(3)dmp2']:
              core.set_local_option('SAPT', 'SAPT_LEVEL', 'SAPT2+3')
              core.set_local_option('SAPT', 'DO_THIRD_ORDER', False)
              core.set_local_option('SAPT', 'DO_CCD_DISP', False)
          elif name in ['sapt2+3', 'sapt2+3dmp2']:
              core.set_local_option('SAPT', 'SAPT_LEVEL', 'SAPT2+3')
              core.set_local_option('SAPT', 'DO_THIRD_ORDER', True)
              core.set_local_option('SAPT', 'DO_CCD_DISP', False)
          elif name in ['sapt2+(ccd)', 'sapt2+(ccd)dmp2']:
              core.set_local_option('SAPT', 'SAPT_LEVEL', 'SAPT2+')
              core.set_local_option('SAPT', 'DO_CCD_DISP', True)
          elif name in ['sapt2+(3)(ccd)', 'sapt2+(3)(ccd)dmp2']:
              core.set_local_option('SAPT', 'SAPT_LEVEL', 'SAPT2+3')

This file has been truncated. show original

You would need to do the deltaMP2 correction manually as well:

github.com

psi4/psi4/blob/master/psi4/driver/procrouting/proc.py#L4237

    
      
          core.IO.set_default_namespace('monomerB')
          core.print_out('\n')
          p4util.banner('Monomer B HF')
          core.print_out('\n')
          
          
core.timer_on("SAPT: Monomer B SCF")
          monomerB_wfn = scf_helper('RHF', molecule=monomerB, **kwargs)
          core.timer_off("SAPT: Monomer B SCF")
          
          
# Delta MP2
          if do_delta_mp2:
              select_mp2(name, ref_wfn=monomerB_wfn, **kwargs)
              mp2_corl_interaction_e -= core.variable('MP2 CORRELATION ENERGY')
              core.set_variable("SAPT MP2 CORRELATION ENERGY", mp2_corl_interaction_e)  # P::e SAPT
          core.set_global_option('DF_INTS_IO', df_ints_io)
          
          
if core.get_option('SCF', 'REFERENCE') == 'RHF':
              core.IO.change_file_namespace(psif.PSIF_SAPT_MONOMERA, 'monomerA', 'dimer')
              core.IO.change_file_namespace(psif.PSIF_SAPT_MONOMERB, 'monomerB', 'dimer')
          
          
core.IO.set_default_namespace('dimer')

Maybe it is actually easier then to copy the run_sapt function and make your own.

For open-shell only SAPT0 is available AFAIK.