Two-electron integrals: *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 will ten to the power of these numbers. By default the same screening threshold will be used for Coulomb and exchange contribution with a default value of .

.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. Defalt value is 9, corresponding to an integral accuracy of .

.PANAS  

Calculates scaled two-electron integrals as proposed by Panas as a simple way of introducing electron correlation in calculations of molecular energies [73].

.PRINT  

READ (LUCMD, '(5I5)') 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 (5I5). The print level is changed from the default for this quadruplet only. Default value is the value of IPRDEF from the **INTEGRALS   input module.

.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 implemented.

.THRFAC  

Not used in DALTON .

.TIME  

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