Energy

energy(name[, bypass_scf, molecule])

Function to compute the single-point electronic energy.

Returns:(float) Total electronic energy in Hartrees. SAPT returns interaction energy. Psi variables:

CURRENT ENERGY CURRENT REFERENCE ENERGY CURRENT CORRELATION ENERGY

name	calls method
scf	Hartree–Fock (HF) or density functional theory (DFT)
mp2	2nd-order Moller-Plesset perturbation theory (MP2)
df-mp2	MP2 with density fitting
dcft	density cumulant functional theory
mcscf	multiconfigurational self consistent field (SCF)
sapt0	0th-order symmetry adapted perturbation theory (SAPT)
sapt2	2nd-order SAPT, traditional definition
sapt2+	SAPT including all 2nd-order terms
sapt2+(3)	SAPT including perturbative triples
sapt2+3
sapt0-ct	0th-order SAPT plus charge transfer (CT) calculation
sapt2-ct	SAPT2 plus CT
sapt2+-ct	SAPT2+ plus CT
sapt2+(3)-ct	SAPT2+(3) plus CT
sapt2+3-ct	SAPT2+3 plus CT
cc2	approximate coupled cluster singles and doubles (CC2)
ccsd	coupled cluster singles and doubles (CCSD)
bccd	Brueckner coupled cluster doubles (BCCD)
cc3	approximate coupled cluster singles, doubles, and triples (CC3)
ccsd(t)	CCSD with perturbative triples
bccd(t)	BCCD with perturbative triples
ccenergy	expert full control over ccenergy module
mpn	nth-order Moller–Plesset perturbation theory
zaptn	nth-order z-averaged perturbation theory (ZAPT)
cisd	configuration interaction (CI) singles and doubles (CISD)
cisdt	CI singles, doubles, and triples (CISDT)
cisdtq	CI singles, doubles, triples, and quadruples (CISDTQ)
cin	nth-order CI
fci	full configuration interaction (FCI)
detci	expert full control over detci module
adc	2nd-order algebraic diagrammatic construction (ADC)
eom-cc2	EOM-CC2
eom-ccsd	equation of motion (EOM) CCSD
eom-cc3	EOM-CC3

name	calls method (aliases to name = ‘scf’)
hf	HF
rhf	HF with restricted reference
uhf	HF with unrestricted reference
rohf	HF with restricted open-shell reference
rscf	HF or DFT with restricted reference
uscf	HF or DFT with unrestricted reference
roscf	HF or DFT with restricted open-shell reference
df-scf	HF or DFT with density fitting

name	calls method
b3lyp	B3LYP Hybrid-GGA Exchange-Correlation Functional
b3lyp-d	B3LYP Hybrid-GGA Exchange-Correlation Functional w/ Grimme’s -D2 Dispersion Correction
b3lyp5	B3LYP5 Hybrid-GGA Exchange-Correlation Functional
b3lyp5-d	B3LYP5 Hybrid-GGA Exchange-Correlation Functional w/ Grimme’s -D2 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
blyp	BLYP GGA Exchange-Correlation Functional
blyp-d	BLYP GGA Exchange-Correlation Functional w/ Grimme’s -D2 Dispersion Correction
bp86	BP86 GGA Exchange-Correlation Functional
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
hcth147	HCTH147 Pure-GGA Exchange-Correlation Functional
hcth407	HCTH407 Pure-GGA Exchange-Correlation Functional
lyp_c	LYP Correlation
m05	Heavily Parameterized Hybrid Meta-GGA XC Functional
m05-2x	Heavily Parameterized Hybrid Meta-GGA XC Functional
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
pbe0	PBE0 Hybrid GGA Exchange-Correlation Functional
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
pw92_c
pz81_c	PZ81 Correlation
svwn	SVWN3 (RPA) LSDA Functional
s_x	Slater LSDA Exchange
vwn3rpa_c	VWN3 (RPA) LSDA Correlation
vwn3_c	VWN3 LSDA Correlation
vwn5rpa_c	VWN5 (RPA) LSDA Correlation
vwn5_c	VWN5 LSDA Correlation
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)
wpbe0	PBE0 SR-XC Functional (HJS Model)
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)
wsvwn	LSDA SR-XC Functional
ws_x	Slater Short-Range LSDA Exchange

name	calls method in Kallay’s MRCC program
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)

Parameters:

• name (string) –

  'scf' || 'df-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.

• bypass_scf (boolean) –

  'on' || 'off'

  Indicates whether, for name values built atop of scf calculations, the scf step is skipped. Suitable when special steps are taken to get the scf to converge in an explicit preceeding scf step.

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
>>> energy('sapt0-ct',cast_up=True)

>>> # [3] Arbitrary-order MPn calculation
>>> energy('mp4')