1. MO integrals

Please try the following job

$molecule

0 1

O

H1 O OH

H2 O OH H1 HOH

OH = 0.947

HOH = 105.5

$end

$rem

EXCHANGE HF

BASIS 3-21G*

SCF_CONVERGENCE 8

IPRINT 200

CORRELATION 105

SAVE_MO_INTEGRALS 2

$end

MO integrals should be printed in the output file. If the scratch directory is saved, binary file 22.0 keeps all significant integrals, another binary file 809.0 keeps the indices. The first entry in file 809.0 is double precision, and tells us how many integrals we saved in 22.0, the next four entries are integers and correspond to the p, q, r, s index for the first MO integral (p, q for the first electron and r, s for the second electron), .... If I remember correctly, we obtain un-anti-symmetrized MO integrals in restricted cases and anti-symmetrized ones in unrestricted cases.

2. AO integrals

Please try

$rem

EXCHANGE HF

BASIS 3-21G*

SCF_CONVERGENCE 8

SCF_GUESS CORE

MAXSCF 2

SAVE_AO_INTEGRALS 1

USE_NEW_PATH2 FALSE

SYMMETRY FALSE

PURECART 22222

$end

and all NBas*NBas*NBas*NBas integrals are kept in file 21.0. Note that it only works for a) purecart=22222 (6d10f15g) and b) with symmetry off.

We can also keep only significant integrals with "save_ao_integrals 2", where file 21.0 keeps the AO integrals and 801.0 keeps the number of significant integrals and then the indices.

I also built the Hartree-Fock exchange matrix directly from these stored AO integrals and, in the output file, this matrix should be shown to match the normal one.

I added both "save_mo_integrals" and "save_ao_integrals" keywords in Q-Chem. Please let me know how well it works for you.

« Last edit by

yihan on Wed Nov 30, 2011 4:08 am. »