On Sun, Nov 16, 2014, Francesco Pietra wrote:
>
> antechamber -fi pdb -i filename.pdb -fo ac -nc -1 -m 2 -c bcc -o
> filename.ac -pf y -s
>
> reports sqm.out
> QMMM: System specified with odd number of electrons ( 61)
> QMMM: but odd spin ( 1). You most likely have the charge of
> QMMM: QM region (qmcharge) set incorrectly. Correct error and re-run
> calculation.
>
>
> There are four N-atoms in the small molecule. Two normal tricoord N, one
> dicoord N with lone pair, one dicoord N with single electron. I could
> calculate RESP charges and carried out frequency analysis ab initio HF
> 6-31G* with a qm package, though still interested in the ac file. Can't
> understand why with 85 electrons, charge -1 mult 2 is said impossible by
> antechamber. I am at ambertools 12.
Check the sqm.in file: it looks like antechamber might not be correctly
passing the "-m " flag info(?).
Also note that bcc charges (and the who antechaber typing scheme) are only
parameterized for closed shell systems. Since you have (or can get) RESP
charges, those would seem to best way to go. Setting up force fields for
organic radicals is uncharted territory, certainly for antechamber.
....dac
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Received on Sun Nov 16 2014 - 13:30:03 PST
