Ground state first-order properties: *CCFOP

In this Section, the keywords for the calculation of ground-state first-order (one-electron) properties are described. The calculation is evoked with the *CCFOP flag followed by the appropriate keywords as described in the list below. Note that *CCFOP assumes that the proper integrals are written on the AOPROPER file, and one therefore has to set the correct property integral keyword(s) in the **INTEGRALS input Section. For properties that have both an electronic and a nuclear contribution, these will be printed separately with a print level of 10 or above.

The calculation of first-order properties is implemented for the coupled cluster models CCS (which gives SCF first-order properties), CC2, MP2, CCD, CCSD and CCSD(T). By default, the chosen properties include orbital relaxation contributions, i.e. they are calculated from the relaxed CC (or MP) densities. To disable orbital relaxation for the CC2 and CCSD models, see .NONREL below. Relaxation is always included for MP2. Note also that the present implementation does not allow for CC2 relaxed first-order properties in the frozen core approximation (.FREEZE and .FROIMP, see Sec. 27.1).

For details on the implementation, see Refs. [181,182,183].

.2ELDAR

Calculate relativistic two-electron Darwin term.

.ALLONE

Calculate all first-order properties described in this Section (all corresponding property integrals are needed).

.DIPMOM

Calculate the permanent molecular electric dipole moment (DIPLEN integrals).

.NONREL

Compute the properties using the unrelaxed CC densities instead of the default relaxed densities.

.NQCC

Calculate the electric field gradients at the nuclei (EFGCAR integrals).

.OPERAT

READ (LUCMD,'(1X,A8)') LABPROP
Calculate the electronic contribution to the property defined by the operator label LABPROP (corresponding LABPROP integrals needed).

.QUADRU

Calculate the permanent traceless molecular electric quadrupole moment (THETA integrals). Note that the origin is the origin of the coordinate system specified in the MOLECULE.INP file.

.RELCOR

Calculate scalar-relativistic one-electron corrections to the ground-state energy (DARWIN and MASSVELO integrals).

.SECMOM

Calculate the electronic second moment of charge (SECMOM integrals).

.TSTDEN

Calculate the CC energy using the two-electron CC density. Programmers keyword used for debugging purposes--Do not use.