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Re: MCSCF calculations stop without any message

Alex Granovsky


there is nothing wrong. The only problem is that the active space
is huge (in this particular case, the NACT**NELS or 328
or ~ 1012 determinants should be a rather good estimate).
The active space does not fit memory and that's why Firefly
aborts job. It would be better if Firefly prints some message
in this situation but it does not do this in all situations at moment.

Do you really need such a large active space? I'd suggest to cut
significantly it until it fits, then perform CASSCF followed by XMCQDPT2 calculations.

Kind regards,
Alex Granovsky

On Tue Feb 21 '12 1:49pm, Mikhail wrote
>Can anybody explain what is wrong with my MCSCF calculations of Th2 molecule?
>Details: runtyp=ENERGY cistep=ALDET. Active space is natural, since ECP removes 156 deep-core electrons, the rest 24 electrons must belong to two 6s orbitals (4 electrons) and to six 6p orbitals (12 electrons) and the rest 8 electrons are certainly active (can take part in chemical bonding) and are dietributed over two 7s, ten 6d, fourteen 5f and six 7p orbitals. Thus, in $DET I specify NCORE=8 (6s and 6p) NACT=32 NELS=8. The result is abnormal end without any information in out file. I tried to use various initial orbitals such as HCORE oe after RHF or UHF run of this molecule, I also shanged MULT (1 or 3). The results were the same.
>Three pairs of INPUT and OUT files are attached.


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