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Re^2: CASSCF optimized orbitals are not orthogonal for XMCQDPT

Alex Granovsky


the origin of the problem is that you have used coord=cart.
The input molecular geometry was reoriented at the very early stage
and thus computed orbitals are for this reoriented geometry.
Fortunately, there is a printout of the new coordinates (in bohr)
at the beginning of the MCSCF output file so one can use them.
Attached please find the fixed xmcqdpt2 input file attached
to my next post. Unless you really need coord=cart and know exactly
what you are doing, it is generally bad idea to use coord=cart.
Use coord=unique (the default settings) instead.

Alex Granovsky

On Fri Mar 25 '11 7:31pm, Gena wrote
>On Fri Mar 25 '11 5:58pm, Gena wrote
>>I try to calculate electronic absorption spectra using XMCQDPT. But after CASSCF calculation is successfully finished, XMCQDPT calculation with optimized MOs from CASSCF PUNCH-file fails in the very beginning listing unorthogonal to each other orbitals, and as i see it - they're all unorthogonal. Firefly also advises me to set INORB=0 to reorthogonalize them. But as XMCQDPT isn't parallel, it isn't convenient. Moreover, i don't understand the difference, i thought that would be the same CASSCF calculation, only in serial mode. Sorry for stupid question, i'm just studying multiconfigurational methods. What am i doing wrong?

[ This message was edited on Mon Mar 28 '11 at 1:29am by the author ]

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