Regarding the DENSity keyword in CASPT2 module
Dear OpenMolcas developers
I found the multi-state CASPT2/RASPT2 energies with the DENSity keyword are very different from the ones without the DENSity keyword.
I'm not sure that the result should change drastically with/without the DENSity keyword as shown below.
If I'm doing wrong, please let me know.
Best regards, Satoi
Energy calculation without DENS keyword: Input nodens.in.txt / Output nodens.out.txt
Effective Hamiltonian matrix (Symmetric):
1 2
1 -0.54159806
2 -0.01798819 -0.29263778
Total RMS-CASPT2 energies:
:: RMS-CASPT2 Root 1 Total energy: -155.54289105
:: RMS-CASPT2 Root 2 Total energy: -155.29134479
E(2) - E(1) = 6.84 eV
Energy calculation with DENS keyword: Input dens.in.txt / Output dens.out.txt
Effective Hamiltonian matrix (Symmetric):
1 2
1 -0.54159806
2 0.13796539 -0.29263778
Total RMS-CASPT2 energies:
:: RMS-CASPT2 Root 1 Total energy: -155.60293976
:: RMS-CASPT2 Root 2 Total energy: -155.23129608
E(2) - E(1) = 10.11 eV