SAPT (DFT) issues

Dear Psi4 community,

I’m facing some troubles with a SAPT(DFT) calculation. I’ve read several posts and on March 29th Professor Sherrill wrote that the code was undergoing testing, but maybe things have changed. My input is very simple and contains a dimer in which He atom and Ar atom are the fragments. When I run the calculation using Psi4 1.3.2-ecbda83 version, I got an output with nonphysical energies in the DF-RKS part for the He fragment. For example, this is what I got in Iter 8.

@DF-RKS iter 8: 5.8228501255924

and from that point on an energy about the same value. Of course, the subsequent SAPT calculations will produce meaningless results.

Here my input

#! SAPT(DFT) aug-cc-pVDZ interaction energy between He and Ar atoms.

molecule dimer {
Ar 1 6.5
units bohr

set {
basis aug-cc-pvdz
scf_type df
sapt_dft_grac_shift_a 0.32033
sapt_dft_grac_shift_b 0.19999

energy(‘sapt(dft)’, molecule=dimer)

Actually, my system is a little bit more complicated and it consists in endohedral fullerenes. In those cases in which I have fragments like He2, HeNe, HeAr, good results are obtained, but when I use He inside the cage, something alters the DF-RKS part of the program, as in the case of the simple HeAr dimer I mentioned before.

Thanks in advance for your help,



Hi Sara,

Thanks for the info!

Unfortunately, we hit a tricky problem that is taking quite a while to work out, and our testing of the SAPT(DFT) code is still not done. However, while we are working on it, we can take a look at this problem as well.