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Single-Point Energy, energy()

energy(name[, molecule, return_wfn, restart_file])[source]

Function to compute the single-point electronic energy.

Returns:float – Total electronic energy in Hartrees. SAPT & EFP return interaction energy.
Returns:(float, Wavefunction) – energy and wavefunction when return_wfn specified.
PSI variables:
Parameters:
  • name (string) –

    'scf' || 'mp2' || 'ci5' || etc.

    First argument, usually unlabeled. Indicates the computational method to be applied to the system.

  • molecule (molecule) –

    h2o || etc.

    The target molecule, if not the last molecule defined.

  • return_wfn (boolean) –

    'on' || \Rightarrow 'off' \Leftarrow

    Indicate to additionally return the Wavefunction calculation result as the second element (after float energy) of a tuple.

  • restart_file (string) –

    ['file.1, file.32] || ./file || etc.

    Binary data files to be renamed for calculation restart.

name calls method
efp effective fragment potential (EFP) [manual]
scf Hartree–Fock (HF) or density functional theory (DFT) [manual]
hf HF self consistent field (SCF) [manual]
dcft density cumulant functional theory [manual]
mp2 2nd-order Moller-Plesset perturbation theory (MP2) [manual] [details]
mp3 3rd-order Moller-Plesset perturbation theory (MP3) [manual] [details]
fno-mp3 MP3 with frozen natural orbitals [manual]
mp2.5 average of MP2 and MP3 [manual] [details]
mp4(sdq) 4th-order MP perturbation theory (MP4) less triples [manual]
fno-mp4(sdq) MP4 (less triples) with frozen natural orbitals [manual]
mp4 full MP4 [manual] [details]
fno-mp4 full MP4 with frozen natural orbitals [manual]
mpn nth-order Moller–Plesset (MP) perturbation theory [manual]
zaptn nth-order z-averaged perturbation theory (ZAPT) [manual]
omp2 orbital-optimized second-order MP perturbation theory [manual]
scs-omp2 spin-component scaled OMP2 [manual]
scs(n)-omp2 a special version of SCS-OMP2 for nucleobase interactions [manual]
scs-omp2-vdw a special version of SCS-OMP2 (from ethene dimers) [manual]
sos-omp2 spin-opposite scaled OMP2 [manual]
sos-pi-omp2 A special version of SOS-OMP2 for pi systems [manual]
omp3 orbital-optimized third-order MP perturbation theory [manual]
scs-omp3 spin-component scaled OMP3 [manual]
scs(n)-omp3 a special version of SCS-OMP3 for nucleobase interactions [manual]
scs-omp3-vdw a special version of SCS-OMP3 (from ethene dimers) [manual]
sos-omp3 spin-opposite scaled OMP3 [manual]
sos-pi-omp3 A special version of SOS-OMP3 for pi systems [manual]
omp2.5 orbital-optimized MP2.5 [manual]
lccsd, cepa(0) coupled electron pair approximation variant 0 [manual] [details]
fno-lccsd, fno-cepa(0) CEPA(0) with frozen natural orbitals [manual]
cepa(1) coupled electron pair approximation variant 1 [manual]
fno-cepa(1) CEPA(1) with frozen natural orbitals [manual]
cepa(3) coupled electron pair approximation variant 3 [manual]
fno-cepa(3) CEPA(3) with frozen natural orbitals [manual]
acpf averaged coupled-pair functional [manual]
fno-acpf ACPF with frozen natural orbitals [manual]
aqcc averaged quadratic coupled cluster [manual]
fno-aqcc AQCC with frozen natural orbitals [manual]
qcisd quadratic CI singles doubles (QCISD) [manual]
fno-qcisd QCISD with frozen natural orbitals [manual]
lccd Linear CCD [manual] [details]
fno-lccd LCCD with frozen natural orbitals [manual]
olccd orbital optimized LCCD [manual]
cc2 approximate coupled cluster singles and doubles (CC2) [manual]
ccd coupled cluster doubles (CCD) [manual]
ccsd coupled cluster singles and doubles (CCSD) [manual] [details]
bccd Brueckner coupled cluster doubles (BCCD) [manual]
fno-ccsd CCSD with frozen natural orbitals [manual]
qcisd(t) QCISD with perturbative triples [manual]
fno-qcisd(t) QCISD(T) with frozen natural orbitals [manual]
ccsd(t) CCSD with perturbative triples (CCSD(T)) [manual] [details]
ccsd(at) CCSD with asymmetric perturbative triples (CCSD(AT)) [manual] [details]
bccd(t) BCCD with perturbative triples [manual]
fno-ccsd(t) CCSD(T) with frozen natural orbitals [manual]
cc3 approximate CC singles, doubles, and triples (CC3) [manual]
ccenergy expert full control over ccenergy module
dfocc expert full control over dfocc module
cisd configuration interaction (CI) singles and doubles (CISD) [manual] [details]
fno-cisd CISD with frozen natural orbitals [manual]
cisdt CI singles, doubles, and triples (CISDT) [manual]
cisdtq CI singles, doubles, triples, and quadruples (CISDTQ) [manual]
cin nth-order CI [manual]
fci full configuration interaction (FCI) [manual]
detci expert full control over detci module
casscf complete active space self consistent field (CASSCF) [manual]
rasscf restricted active space self consistent field (RASSCF) [manual]
mcscf multiconfigurational self consistent field (SCF) [manual]
psimrcc Mukherjee multireference coupled cluster (Mk-MRCC) [manual]
dmrg-scf density matrix renormalization group SCF [manual]
dmrg-caspt2 density matrix renormalization group CASPT2 [manual]
dmrg-ci density matrix renormalization group CI [manual]
sapt0 0th-order symmetry adapted perturbation theory (SAPT) [manual]
ssapt0 0th-order SAPT with special exchange scaling [manual]
sapt2 2nd-order SAPT, traditional definition [manual]
sapt2+ SAPT including all 2nd-order terms [manual]
sapt2+(3) SAPT including perturbative triples [manual]
sapt2+3 SAPT including all 3rd-order terms [manual]
sapt2+(ccd) SAPT2+ with CC-based dispersion [manual]
sapt2+(3)(ccd) SAPT2+(3) with CC-based dispersion [manual]
sapt2+3(ccd) SAPT2+3 with CC-based dispersion [manual]
sapt2+dmp2 SAPT including all 2nd-order terms and MP2 correction [manual]
sapt2+(3)dmp2 SAPT including perturbative triples and MP2 correction [manual]
sapt2+3dmp2 SAPT including all 3rd-order terms and MP2 correction [manual]
sapt2+(ccd)dmp2 SAPT2+ with CC-based dispersion and MP2 correction [manual]
sapt2+(3)(ccd)dmp2 SAPT2+(3) with CC-based dispersion and MP2 correction [manual]
sapt2+3(ccd)dmp2 SAPT2+3 with CC-based dispersion and MP2 correction [manual]
sapt0-ct 0th-order SAPT plus charge transfer (CT) calculation [manual]
sapt2-ct SAPT2 plus CT [manual]
sapt2+-ct SAPT2+ plus CT [manual]
sapt2+(3)-ct SAPT2+(3) plus CT [manual]
sapt2+3-ct SAPT2+3 plus CT [manual]
sapt2+(ccd)-ct SAPT2+(CCD) plus CT [manual]
sapt2+(3)(ccd)-ct SAPT2+(3)(CCD) plus CT [manual]
sapt2+3(ccd)-ct SAPT2+3(CCD) plus CT [manual]
adc 2nd-order algebraic diagrammatic construction (ADC) [manual]
eom-cc2 EOM-CC2 [manual]
eom-ccsd equation of motion (EOM) CCSD [manual]
eom-cc3 EOM-CC3 [manual]
name calls method DFT [manual]
b2plyp B2PLYP Double Hybrid Exchange-Correlation Functional
b2plyp-d B2PLYP Double Hybrid Exchange-Correlation Functional w/ Grimme’s -D2 Dispersion Correction
b2plyp-d3 B2PLYP Double Hybrid Exchange-Correlation Functional w/ Grimme’s -D3 (zero-damping) Dispersion Correction
b2plyp-d3bj B2PLYP Double Hybrid Exchange-Correlation Functional w/ Grimme’s -D3 (BJ-damping) Dispersion Correction
b2plyp-d3m B2PLYP Double Hybrid Exchange-Correlation Functional w/ Grimme’s -D3 (zero-damping, short-range refitted) Dispersion Correction
b2plyp-d3mbj B2PLYP Double Hybrid Exchange-Correlation Functional w/ Grimme’s -D3 (BJ-damping, short-range refitted) Dispersion Correction
b3lyp B3LYP Hybrid-GGA Exchange-Correlation Functional (VWN1-RPA)
b3lyp-chg B3LYP Hybrid-GGA Exchange-Correlation Functional (VWN1-RPA) w/ Chai and Head-Gordon Dispersion Correction
b3lyp-d B3LYP Hybrid-GGA Exchange-Correlation Functional (VWN1-RPA) w/ Grimme’s -D2 Dispersion Correction
b3lyp-d1 B3LYP Hybrid-GGA Exchange-Correlation Functional (VWN1-RPA) w/ Grimme’s -D1 Dispersion Correction
b3lyp-d3 B3LYP Hybrid-GGA Exchange-Correlation Functional (VWN1-RPA) w/ Grimme’s -D3 (zero-damping) Dispersion Correction
b3lyp-d3bj B3LYP Hybrid-GGA Exchange-Correlation Functional (VWN1-RPA) w/ Grimme’s -D3 (BJ-damping) Dispersion Correction
b3lyp-d3m B3LYP Hybrid-GGA Exchange-Correlation Functional (VWN1-RPA) w/ Grimme’s -D3 (zero-damping, short-range refitted) Dispersion Correction
b3lyp-d3mbj B3LYP Hybrid-GGA Exchange-Correlation Functional (VWN1-RPA) w/ Grimme’s -D3 (BJ-damping, short-range refitted) Dispersion Correction
b3lyp5 B3LYP5 Hybrid-GGA Exchange-Correlation Functional (VWN5)
b3lyp5-d B3LYP5 Hybrid-GGA Exchange-Correlation Functional (VWN5) w/ Grimme’s -D2 Dispersion Correction
b3lyp5-d3 B3LYP5 Hybrid-GGA Exchange-Correlation Functional (VWN5) w/ Grimme’s -D3 (zero-damping) Dispersion Correction
b3lyp5-d3bj B3LYP5 Hybrid-GGA Exchange-Correlation Functional (VWN5) w/ Grimme’s -D3 (BJ-damping) Dispersion Correction
b3lyp5-d3m B3LYP5 Hybrid-GGA Exchange-Correlation Functional (VWN5) w/ Grimme’s -D3 (zero-damping, short-range refitted) Dispersion Correction
b3lyp5-d3mbj B3LYP5 Hybrid-GGA Exchange-Correlation Functional (VWN5) w/ Grimme’s -D3 (BJ-damping, short-range refitted) Dispersion Correction
b3_x Becke88 GGA Exchange (B3LYP weighting)
b88_x Becke88 GGA Exchange
b97-0 B97-0 Hybrid-GGA Exchange-Correlation Functional
b97-1 B97-1 Hybrid-GGA Exchange-Correlation Functional
b97-2 B97-2 Hybrid-GGA Exchange-Correlation Functional
b97-d B97-D Pure-GGA Exchange-Correlation Functional w/ Grimme’s -D2 Dispersion Correction
b97-d3 B97-D Pure-GGA Exchange-Correlation Functional w/ Grimme’s -D3 (zero-damping) Dispersion Correction
b97-d3bj B97-D Pure-GGA Exchange-Correlation Functional w/ Grimme’s -D3 (BJ-damping) Dispersion Correction
b97-d3m B97-D Pure-GGA Exchange-Correlation Functional w/ Grimme’s -D3 (zero-damping, short-range refitted) Dispersion Correction
b97-d3mbj B97-D Pure-GGA Exchange-Correlation Functional w/ Grimme’s -D3 (BJ-damping, short-range refitted) Dispersion Correction
blyp BLYP GGA Exchange-Correlation Functional
blyp-d BLYP GGA Exchange-Correlation Functional w/ Grimme’s -D2 Dispersion Correction
blyp-d1 B3LYP Hybrid-GGA Exchange-Correlation Functional (VWN1-RPA) w/ Grimme’s -D1 Dispersion Correction
blyp-d3 BLYP GGA Exchange-Correlation Functional w/ Grimme’s -D3 (zero-damping) Dispersion Correction
blyp-d3bj BLYP GGA Exchange-Correlation Functional w/ Grimme’s -D3 (BJ-damping) Dispersion Correction
blyp-d3m BLYP GGA Exchange-Correlation Functional w/ Grimme’s -D3 (zero-damping, short-range refitted) Dispersion Correction
blyp-d3mbj BLYP GGA Exchange-Correlation Functional w/ Grimme’s -D3 (BJ-damping, short-range refitted) Dispersion Correction
bp86 BP86 GGA Exchange-Correlation Functional
bp86-d BP86 GGA Exchange-Correlation Functional w/ Grimme’s -D2 Dispersion Correction
bp86-d1 BP86 GGA Exchange-Correlation Functional w/ Grimme’s -D1 Dispersion Correction
bp86-d3 BP86 GGA Exchange-Correlation Functional w/ Grimme’s -D3 (zero-damping) Dispersion Correction
bp86-d3bj BP86 GGA Exchange-Correlation Functional w/ Grimme’s -D3 (BJ-damping) Dispersion Correction
bp86-d3m BP86 GGA Exchange-Correlation Functional w/ Grimme’s -D3 (zero-damping, short-range refitted) Dispersion Correction
bp86-d3mbj BP86 GGA Exchange-Correlation Functional w/ Grimme’s -D3 (BJ-damping, short-range refitted) Dispersion Correction
ft97 FT97 GGA Exchange-Correlation Functional
ft97b_x Filitov and Theil 1997 Exchange
ft97_c FT97 Correlation (Involves Ei functions)
hcth HCTH Pure-GGA Exchange-Correlation Functional
hcth120 HCTH120 Pure-GGA Exchange-Correlation Functional
hcth120-d3 HCTH120 Pure-GGA Exchange-Correlation Functional w/ Grimme’s -D3 (zero-damping) Dispersion Correction
hcth120-d3bj HCTH120 Pure-GGA Exchange-Correlation Functional w/ Grimme’s -D3 (BJ-damping) Dispersion Correction
hcth147 HCTH147 Pure-GGA Exchange-Correlation Functional
hcth407 HCTH407 Pure-GGA Exchange-Correlation Functional
hf+d w/ Podeszwa and Szalewicz Dispersion Correction
hf_x Hartree-Fock Exchange Functional
lyp_c LYP Correlation
m05 Heavily Parameterized Hybrid Meta-GGA XC Functional
m05-2x Heavily Parameterized Hybrid Meta-GGA XC Functional
m05-2x-d3 Heavily Parameterized Hybrid Meta-GGA XC Functional w/ Grimme’s -D3 (zero-damping) Dispersion Correction
m05-d3 Heavily Parameterized Hybrid Meta-GGA XC Functional w/ Grimme’s -D3 (zero-damping) Dispersion Correction
p86_c P86 Correlation (PZ81 LSDA + P86 GGA)
pbe PBE GGA Exchange-Correlation Functional
pbe-d PBE GGA Exchange-Correlation Functional w/ Grimme’s -D2 Dispersion Correction
pbe-d1 PBE GGA Exchange-Correlation Functional w/ Grimme’s -D1 Dispersion Correction
pbe-d3 PBE GGA Exchange-Correlation Functional w/ Grimme’s -D3 (zero-damping) Dispersion Correction
pbe-d3bj PBE GGA Exchange-Correlation Functional w/ Grimme’s -D3 (BJ-damping) Dispersion Correction
pbe-d3m PBE GGA Exchange-Correlation Functional w/ Grimme’s -D3 (zero-damping, short-range refitted) Dispersion Correction
pbe-d3mbj PBE GGA Exchange-Correlation Functional w/ Grimme’s -D3 (BJ-damping, short-range refitted) Dispersion Correction
pbe0 PBE0 Hybrid GGA Exchange-Correlation Functional
pbe0-2 PBE0-2 Double Hydrid Exchange-Correlation Functional
pbe0-d PBE0 Hybrid GGA Exchange-Correlation Functional w/ Grimme’s -D2 Dispersion Correction
pbe0-d3 PBE0 Hybrid GGA Exchange-Correlation Functional w/ Grimme’s -D3 (zero-damping) Dispersion Correction
pbe0-d3bj PBE0 Hybrid GGA Exchange-Correlation Functional w/ Grimme’s -D3 (BJ-damping) Dispersion Correction
pbe0-d3m PBE0 Hybrid GGA Exchange-Correlation Functional w/ Grimme’s -D3 (zero-damping, short-range refitted) Dispersion Correction
pbe0-d3mbj PBE0 Hybrid GGA Exchange-Correlation Functional w/ Grimme’s -D3 (BJ-damping, short-range refitted) Dispersion Correction
pbea_c New Implementation of PBEC in wPBEc-sr.
pbesol_x PBEsol GGA Exchange Hole (Parameter Free)
pbe_c PBE Correlation
pbe_x PBE GGA Exchange Hole (Parameter Free)
pw91 PW91 GGA Exchange-Correlation Functional
pw91_c PW91 Correlation
pw91_x PW91 Parameterized GGA Exchange
pw92a_c New Implementation of PW92C in wPBEc-sr.
pw92_c  
pz81_c PZ81 Correlation
rpbe_x RPBE GGA Exchange Hole (Parameter Free)
sogga Second Order GGA Exchange-Correlation Functional
sogga_x Second Order GGA Exchange Hole (Parameter Free)
svwn SVWN3 (RPA) LSDA Functional
s_x Slater LSDA Exchange
vwn3rpa_c VWN3 LSDA Correlation, RPA Parameters, VWN1 Spin Polarization
vwn3_c VWN3 LSDA Correlation, QMC Parameters, VWN1 Spin Polarization
vwn5rpa_c VWN5 LSDA Correlation, RPA Parameters, VWN5 Spin Polarization
vwn5_c VWN5 LSDA Correlation, QMC Parameters, VWN5 Spin Polarization
wpbe-d3 PBE SR-XC Functional (HJS Model) w/ Grimme’s -D3 (zero-damping) Dispersion Correction
wpbe-d3m PBE SR-XC Functional (HJS Model) w/ Grimme’s -D3 (zero-damping, short-range refitted) Dispersion Correction
dldf Dispersionless Hybrid Meta-GGA XC Functional
dldf+d Dispersionless Hybrid Meta-GGA XC Functional w/ Podeszwa and Szalewicz Dispersion Correction
dldf+d09 Dispersionless Hybrid Meta-GGA XC Functional w/ Podeszwa and Szalewicz Dispersion Correction
wb88_x B88 Short-Range GGA Exchange (HJS Model)
wb97 Parameterized LRC B97 GGA XC Functional
wb97x Parameterized Hybrid LRC B97 GGA XC Functional
wb97x-d Parameterized Hybrid LRC B97 GGA XC Functional with Dispersion w/ Chai and Head-Gordon Dispersion Correction
wblyp BLYP SR-XC Functional (HJS Model)
wpbe PBE SR-XC Functional (HJS Model)
wpbe-d3bj PBE SR-XC Functional (HJS Model) w/ Grimme’s -D3 (BJ-damping) Dispersion Correction
wpbe-d3mbj PBE SR-XC Functional (HJS Model) w/ Grimme’s -D3 (BJ-damping, short-range refitted) Dispersion Correction
wpbe0 PBE0 SR-XC Functional (HJS Model)
wpbe2 Double-Hybrid PBE LRC Functional
wpbe_c Short-Range PBE Correlation Functional
wpbe_x PBE Short-Range GGA Exchange (HJS Model)
wpbesol PBEsol SR-XC Functional (HJS Model)
wpbesol0 PBEsol0 SR-XC Functional (HJS Model)
wpbesol_x PBEsol Short-Range GGA Exchange (HJS Model)
wpw92_c Short-Range PW92 Correlation Functional
wsvwn LSDA SR-XC Functional
ws_x Slater Short-Range LSDA Exchange
name calls method in Kallay’s MRCC program [manual]
mrccsd CC through doubles
mrccsdt CC through triples
mrccsdtq CC through quadruples
mrccsdtqp CC through quintuples
mrccsdtqph CC through sextuples
mrccsd(t) CC through doubles with perturbative triples
mrccsdt(q) CC through triples with perturbative quadruples
mrccsdtq(p) CC through quadruples with pertubative quintuples
mrccsdtqp(h) CC through quintuples with pertubative sextuples
mrccsd(t)_l  
mrccsdt(q)_l  
mrccsdtq(p)_l  
mrccsdtqp(h)_l  
mrccsdt-1a CC through doubles with iterative triples (cheapest terms)
mrccsdtq-1a CC through triples with iterative quadruples (cheapest terms)
mrccsdtqp-1a CC through quadruples with iterative quintuples (cheapest terms)
mrccsdtqph-1a CC through quintuples with iterative sextuples (cheapest terms)
mrccsdt-1b CC through doubles with iterative triples (cheaper terms)
mrccsdtq-1b CC through triples with iterative quadruples (cheaper terms)
mrccsdtqp-1b CC through quadruples with iterative quintuples (cheaper terms)
mrccsdtqph-1b CC through quintuples with iterative sextuples (cheaper terms)
mrcc2 approximate CC through doubles
mrcc3 approximate CC through triples
mrcc4 approximate CC through quadruples
mrcc5 approximate CC through quintuples
mrcc6 approximate CC through sextuples
mrccsdt-3 CC through doubles with iterative triples (all but the most expensive terms)
mrccsdtq-3 CC through triples with iterative quadruples (all but the most expensive terms)
mrccsdtqp-3 CC through quadruples with iterative quintuples (all but the most expensive terms)
mrccsdtqph-3 CC through quintuples with iterative sextuples (all but the most expensive terms)
name calls method in Stanton and Gauss’s CFOUR program [manual]
c4-scf Hartree–Fock (HF)
c4-mp2 2nd-order Moller-Plesset perturbation theory (non-density-fitting) (MP2)
c4-mp3 3rd-order Moller-Plesset perturbation theory (MP3)
c4-mp4(sdq) 4th-order MP perturbation theory (MP4) less triples
c4-mp4 full MP4
c4-cc2 approximate coupled cluster singles and doubles (CC2)
c4-ccsd coupled cluster singles and doubles (CCSD)
c4-cc3 approximate CC singles, doubles, and triples (CC3)
c4-ccsd(t) CCSD with perturbative triples (CCSD(T))
c4-ccsdt coupled cluster singles, doubles, and triples (CCSDT)
cfour expert full control over cfour program
Examples:
>>> # [1] Coupled-cluster singles and doubles calculation with psi code
>>> energy('ccsd')
>>> # [2] Charge-transfer SAPT calculation with scf projection from small into
>>> #     requested basis, with specified projection fitting basis
>>> set basis_guess true
>>> set df_basis_guess jun-cc-pVDZ-JKFIT
>>> energy('sapt0-ct')
>>> # [3] Arbitrary-order MPn calculation
>>> energy('mp7')
>>> # [4] Converge scf as singlet, then run detci as triplet upon singlet reference
>>> # Note that the integral transformation is not done automatically when detci is run in a separate step.
>>> molecule H2 {\n0 1\nH\nH 1 0.74\n}
>>> set global basis cc-pVDZ
>>> set global reference rohf
>>> scf_e, scf_wfn = energy('scf', return_wfn = True)
>>> H2.set_multiplicity(3)
>>> psi4.MintsHelper(scf_wfn.basisset()).integrals()
>>> energy('detci', ref_wfn=scf_wfn)
>>> # [5] Run two CI calculations, keeping the integrals generated in the first one.
>>> molecule ne {\nNe\n}
>>> set globals  basis cc-pVDZ
>>> cisd_e, cisd_wfn = energy('cisd', return_wfn = True)
>>> energy('fci', ref_wfn=cisd_wfn)
>>> # [6] Can automatically perform complete basis set extrapolations
>>> energy("MP2/cc-pV[DT]Z")