First, please, let me send you a big, big THANK YOU for making such excellent quantum chemistry software available open source to the general public!
Unfortunately, it seems, I hit a bug:
I computed the HF energies for B+ (4 electrons) with an
aug-cc-pcv[t,q,5,6]z basis.
Here are the HF energies from Psi4 (left) and from a well-known other program (right):
aug-cc-pcvtz -24.23687687337318 -24.236876244574
aug-cc-pcvqz -23.75349206862587 -24.237476720808
aug-cc-pcv5z -23.75374913354539 -24.237547009679
aug-cc-pcv6z -23.75377754514268 -24.237569639624
Here is the same for C2+:
aug-cc-pcvtz -36.40748210426819 -36.407480789809
aug-cc-pcvqz -35.72868177282092 -36.408289781221
aug-cc-pcv5z -35.72921212773497 -36.408419504400
aug-cc-pcv6z -35.72926641187144 -36.408484020785
While the aug-cc-pcvtz values agree, the others differ.
I have no doubt that the other program’s values are OK as those program’s aug-cc-pcv6z CCSD(T) value for B+ agrees well with nearly accurate
literature data.
Nevertheless, again many thanks for this excellent software!
Best regards