Two-electron integrals using ERI: *ER2INT

Directives controlling the two-electron integral calculation with ERI are specified in the *ER2INT section. By default ERI is only used for integral-direct coupled cluster calculations. However, ERI can also be invoked by specifying the .RUNERI keyword in the **DALTON INPUT input section. Note that DALTON will automatically use TWOINT for all integrals not available in ERI.

.AOBTCH

READ (LUCMD,*) IAOBCH

Only integrals with the first integral index belonging to AO batch number IAOBCH will be calculated.

.BUFFER

READ (LUCMD,*) LBFINP

This option may be used to set the buffer length for integrals written to disk. For compatibility with TWOINT, the default buffer length is 600. Longer buffer lengths may give more efficient I/O.

.DISTRI

Use distributions for electron 1. Must be used in connection with the keywork .SELCT1.

.DISTST

Test the calculation of two-electron integrals using distributions.

.DOERIP

Use the ERI integral program for the calculation of two-electron integrals instead of TWOINT.

.EXTPRI

READ (LUCMD,*) IPROD1, IPROD2

Full print for overlap distribution (OD) classes IPROD1 and IPROD2.

.GENCON

Treat all AOs as generally contracted during integral evaluation.

.GRDZER

During evaluation of the molecular gradient, the gradient is set to zero upon each entry into ERIAVE (for debugging).

.INTPRI

Force the printing of calculated two-electron integrals.

.INTSKI

Skip the calculation of two-electron integrals in the ERI calculation.

.MAXDIS

READ (LUCMD,*) MAXDST

Read in the maximimum number of integral distributions calculated in each call to the integral code. Default value is 40.

.MXBCH

READ (LUCMD,*) MXBCH

Read in the maximum number of integral batches to be treated simultaneously, and thus determines the vector lengths. Default value is 1000000000.

.NCLERI

Calculate only integrals with non-classical contributions.

.NEWCR1

Use an old transformation routine for the generation of the Cartesian integrals for electron 1.

.NOLOCS

Do not use local symmetry during evaluation.

.NONCAN

Do not sort integral indices in canonical order. This option is applicable only for undifferentiated integrals written fully to disk (without the use of distributions). This option may save some time but will lead to incorrect results whenever canonical ordering is assumed.

.NO12GS

During sorting of OD batches, treat batches containing one and two distinct AOs as equivalent.

.NOPS12

Do not assume permutational symmetry between the two electrons.

.NOPSAB

Do not assume permutational symmetry between orbitals of electron 1.

.NOPSCD

Do not assume permutational symmetry between orbitals of electron 2.

.NOSCRE

Do not do integral screening before integrals are written to disk.

.NOWRIT

Do not write integrals to disk.

.NSPMAX

READ (LUCMD,*) NSPMAX

Allows for the reduction of the number of symmetry generations for each basis function in order to reduce memory requirements. Mainly for debugging purposes, do not use.

.OFFCNT

During sorting of OD batches, treat batches containing one and two distinct AO centers as equivalent.

.PRINT

READ (LUCMD,*) IPRERI, IPRNT1, IPRNT2

Print level for ERI. By giving numbers different from zero for IPRNT1 and IPRNT2, extra print information may be given for these overlap distributions, after which the program will exit.

.RETURN

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

.SELCT1

READ (LUCMD,*) NSELCT(1)
READ (LUCMD,*) (NACTAO(I,1),I=1,NSELCT(1))

Calculate only integrals containing indices NACTAO(I,1) for the first AO.

.SELCT2

Same as .SELCT1 but for the second AO.

.SELCT3

Same as .SELCT1 but for the third AO.

.SELCT4

Same as .SELCT1 but for the fourth AO.

.SKIP

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

.TIME

Provide detailed timings for the two-electron integral calculation in ERI.

.WRITEA

Write all integrals to disk without any screening.