Dear all,
I'm looking at the isotropic NMR shielding at different points in space around my molecule employing the so-called ghost atoms Bq.
I have created a rather large 2D plane (grid) of 10 000 Bqs. In the input file these follow straight after the coordinates of my molecule.
The GIAO job fails with a message "Maximum number of bonds=100 exceeded for atom 26", this atom being the first Ghost atom listed.
Importantly, there are no bonds between each ghost atom and any other atom, and geom=connectivity keyword has been purposely omitted.
Can you recommend a keyword that would stop the Gaussian 09W to check anything related to bonding, or any alternative way around this issue?
This is the case for when either Z-matrix or Cartesian coordinates are used. SkipAll and NoTest keywords haven't been helpful.
Many thanks,
Eduards
PS. I have found that minimising the numer of Bq atoms to the very arbitrary number of 134 (from the total of 159 atoms in the job) such error is no longer produced and the job runs normally. Is this normal?
Thanks! As can be seen from my question, this already has already been done providing no solution.
In case anyone is having this issue, I think it can be fixed with relative ease by actually inputing the connectivity (geom=connectivity) and explicitly disconnecting the Bq dummies. For an input of, say, water with two Bq dummies, do:
#Method/basisset geom=connectivity
Water with terrible coordinates
0 1
O 0.000 0.000 0.000
H 0.500 0.500 0.000
H -0.500 0.500 0.000
Bq 1.000 0.000 0.000
Bq 2.000 0.000 0.000
1 2 1.0 3 1.0
2
3
4
5
And so on for all the Bqs. That way the program will not attempt to assign a connectivity on its own and the (suspiciously weird) error will not pop.
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