Large difference between semicanonical & standard

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6 years 6 months ago #413 by Nike
Dear all,
The manual says "Iterative CC and CI methods are invariant to the choice of ROHF orbitals", but I have found a large difference for CISD, which doesn't involve (T), (Q), (P), or anything in parenthesis.

Oxygen atom aV8Z 366 functions
CISD -74.996 013 37 (Frozen-core Semicanonical)
CISD -74.996 035 45 (Frozen-core Standard)

Nitrogen atom aV8Z 366 functions
CISD -54.525 222 25 (Semicanonical)
CISD -54.525 259 92 (Standard)

I have attached a GENBAS along with all four output files (which include the inputs).
Actually it seems I can only add 3 attachments in one post, so I have only included the nitrogen atom

Am I doing something wrong, or have I found a bug, or am I interpreting the manual wrong?

With best wishes!
Nike

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6 years 6 months ago #414 by Nike
Attachments for Oxygen added here:

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  • kallay
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6 years 6 months ago #415 by kallay
Dear Nike,
It is only true if all electrons are correlated. With frozen core the energies are slightly different since the frozen orbitals are not identical. I will correct the manual.

Best regards,
Mihaly Kallay

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