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CEPA

General

CEPA_LEVEL

Which coupled-pair method is called? This parameter is used internally by the python driver. Changing its value won’t have any effect on the procedure.

  • Type: string
  • Default: CEPA(0)

CEPA_NO_SINGLES

Flag to exclude singly excited configurations from the computation. Note that this algorithm is not optimized for doubles-only computations.

CEPA_SCALE_OS

Oppposite-spin scaling factor for SCS-CEPA.

  • Type: double
  • Default: 1.27

CEPA_SCALE_SS

Same-spin scaling factor for SCS-CEPA.

  • Type: double
  • Default: 1.13

CEPA_VABCD_DIRECT

Use integral-direct implementation of the (ac|bd) t(ij,cd) contraction? AO integrals will be generated on the fly. The CEPA iterations will be slower, but the AO->MO integral transform will be faster, and the out-of-core sort of the (AC|BD) integrals will be avoided.

DIIS_MAX_VECS

Number of vectors to store for DIIS extrapolation.

  • Type: integer
  • Default: 8

DIPMOM

Compute the dipole moment? Note that quadrupole moments will also be computed if PRINT >= 2.

MAXITER

Maximum number of iterations to converge the t1 and t2 amplitudes.

  • Type: integer
  • Default: 100

MP2_SCALE_OS

Opposite-spin scaling factor for SCS-MP2.

  • Type: double
  • Default: 1.20

MP2_SCALE_SS

Same-spin scaling factor for SCS-MP2

  • Type: double
  • Default: 1.0/3.0

R_CONVERGENCE

Desired convergence for the t1 and t2 amplitudes, defined as the norm of the change in the amplitudes between iterations.

SCS_CEPA

Perform SCS-CEPA? If true, note that the default values for the spin component scaling factors are optimized for the CCSD method.

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