[QE-users] calculation of Coulomb and exchange integrals in QE

[Ivan Carnimeo]

Dear Daniel,

the Hartree term is computed with the electronic density, that is much faster than computing it from the individual Kohn-Sham states contributions, so that Coulomb integrals <ij|ij> are not natively available, at least in the main SCF code.

Exchange integrals are partially computed in vexx and vexx_loc (in exx.f90), you should be able to print them, but you will need some coding.

vexx/vexx_loc compute the exchange potential Vx_i(r) by summing pair contributions of the type "Vx_jji(r)", for each orbital pair i,j. So you will need to take the contribution of a given orbital pair i, j, and left-braket it to recover the integral in the <ij|ji> form.
With some rearrangement of the loop you should be able to compute also the Coulomb integrals.

Regards,
IC

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.quantum-espresso.org/pipermail/users/attachments/20240617/cb96a174/attachment.html>