Two-electron integrals using TWOINT: *TWOINT

Directives affecting the two-electron undifferentiated Hamiltonian integral calculation appear in the *TWOINT section.

.ICEDIF

READ (LUCMD,*) ICDIFF,IEDIFF

Screening threshold for Coulomb and exchange contributions to the Fock matrix in direct and parallel calculations. The thresholds for the integrals are ten to the negative power of these numbers. By default the same screening threshold will be used for Coulomb and exchange contribution which will change dynamically as the wave function converges more and more tightly.

.IFTHRS

READ (LUCMD,*) IFTHRS

Screening threshold used in direct and parallel calculations. The integral threshold will be ten to the negative power of this number. The default is that this value will change dynamically as the wave function converges more and more tightly.

.PANAS

Calculates scaled two-electron integrals as proposed by Panas as a simple way of introducing electron correlation in calculations of molecular energies [125].

.PRINT

READ (LUCMD, *) IPRINT, IPRNTA, IPRNTB, IPRNTC, IPRNTD

Set print level for the derivative integral calculation of a particular shell quadruplet. Read one more line containing print level and the four shell indices. The print level is changed from the default for this quadruplet only.

.RETURN

Stop after the shell quadruplet specified under .PRINT above. Mainly for debugging purposes.

.SKIP

Skip the calculation of two-electron Hamiltonian integrals. An alternative keyword is .NOTWO in the **INTEGRALS input module.

.SOFOCK

Construct the Fock matrix in symmetry-orbital basis during a direct or parallel calculation. Currently not active.

.THRFAC

Not used in DALTON.

.TIME

Provide detailed timing breakdown for the two-electron integral calculation.