I am carrying out a project which involves obtaining the RHF result and the integrals for the chromium dimer (Cr2) under Ahlrichs' SV basis. In the literature against which we attempt to benchmark, the Mg core of each Cr is frozen, yielding 30 orbitals and 24 electrons in total. I thus wonder how should I set up in Molpro to get the cores frozen. My guess is that one should first do something like:

basis = SV 

to obtain the occupied orbitals for a dual Mg system under the same geometry as Cr2's, and next freeze these orbitals in Cr2:


{fci, dump = name

But is this correct? If not, what is the correct way to freeze the cores? Thanks for the help in advance!

  • 1
    $\begingroup$ +1 and welcome to our new community! Thanks for contributing your question here and we hope to see much more of you in the future !!! I've adjusted the title, because it's not the HF calculation in which the core is frozen (freezing usually happens in the post-HF calculations). $\endgroup$ Jul 17, 2022 at 20:53
  • $\begingroup$ How are things going? Did you figure this out? Are you still working on it? I've made an edit which will bump this question up to the top of the front page! $\endgroup$ Jan 31 at 21:38


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