Single-Point Energy — energy()
¶
- Psi4 Native Energy Methods
- Psi4 Native DFT Energy Methods
- MRCC Interfaced Energy Methods
- CFOUR Interfaced Energy Methods
-
psi4.
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.
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 basis cc-pVDZ >>> set reference rohf >>> scf_e, scf_wfn = energy('scf', return_wfn=True) >>> H2.set_multiplicity(3) >>> core.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 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("CCSD/cc-pV[DT]Z")
>>> # [7] Can automatically perform delta corrections that include extrapolations >>> # even with a user-defined extrapolation formula. See sample inputs named >>> # cbs-xtpl* for more examples of this input style >>> energy("MP2/aug-cc-pv([d,t]+d)z + d:ccsd(t)/cc-pvdz", corl_scheme=myxtplfn_2)
- name (string) –