[molpro-user] Why the MCSCF energy is lower than Full-CI?
kipeters at wsu.edu
Sun Feb 14 17:34:22 GMT 2010
I believe the occ directive in your FCI calculation should be the same as the HF reference, i.e., occ,2; or just
leave out both the occ and core directives and take the defaults. For me at least with 2009.2, this then
yields the same energy for FCI and CASSCF.
On Feb 13, 2010, at 7:28 AM, cong.wang wrote:
> Dear everyone,
> Excuse me, I did a HF, CASSCF(4,8), and Full-CI calculations for
> H4 square molecule with 6-31G basis set on molpro 2009. The CASSCF
> energy is lower than FCI by 0.02 a.u., what would be the explanation
> for that? Should the CASSCF(4,8) and FCI be equivalent in this case?
> Here are the input and output files
> Thank you very much in advance
> Best regards
> Cong Wang
> Ph. D. Student
> Department of Chemistry
> Laboratory for Instruction in Swedish
> University of Helsinki
> A.I. Virtanens plats 1
> P.O. Box 55
> FI-00014 University of Helsinki
> ***,h4 !A title
> H 0. 0. 0.
> H 0. 0. 0.5
> H 0. 0.5 0.
> H 0. 0.5 0.5
> ! HYDROGEN (4s) -> [2s]
> s, H , 18.7311370, 2.8253937, 0.6401217, 0.1612778
> c, 1.3, 0.03349460, 0.23472695, 0.81375733
> c, 4.4, 1
> hf !closed-shell scf
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