CP Corrections for Systems Including ECPs

[Connor Fawcett]

Hey Molpro Devs/Community!

I'm currently studying small molecule adsorption on metallic clusters. I'm interested in performing counterpoise corrections to assess the basis set superposition error. However, the default ECP for the copper atoms in my system are causing issues when I try to run my calculations.

For example, if I set Cu atoms to be "dummy" atoms, the ECP of the Cu atoms will still be present in the RKS calculation of the small molecule. Is there a convenient way to still use the default basis set but remove the ECP to resolve this issue?

Here is an example of my input file:

geometry=coords.xyz
symmetry,nosym

gthresh,thrdlov=1.0d-10
gdirect

basis={
default,aug-cc-PVDZ-pp
set,jkfit; default,aug-cc-PVDZ-pp/jkfit}

{int}

dummy,1,-20

{df-uks,pbe,
wf,14,1,0
save,2200.2
}

The geometry contains a Cu cluster with CO adsorbed on the surface. All Cu atoms are declared as "dummies". However, the energy during UKS is very positive (~+9000 hartree)

I've already tried defining the basis functions as part of the aug-cc-PVDZ-PP family individually, however this leads to issues with density fitting as it tries to find a "user defined" jfit set rather than my specified default aug-cc-PVDZ-PP jkfit set. I'll need to keep using density fitting as i'll be using other methods such as ACFDT2 later on.

Please let me know,
Connor

[hjwern...@gmail.com]

I think the problem is that you specified symmetry,nosym after geometry=...

nosym, or symmetry,nosym has to be given before the geometry directive (if at all)