I have been making some failed attempts to calculate interaction energy of 2 monomers using a dummy/ghost atom in NWChem6.5.
The code I was using to calculate the interaction energy is:

title 'bond_energy'
start dimer
geometry units angstrom
  N 5.286 28.124 48.085 
  H 5.966 28.410 48.528 
  O 7.110 29.056 50.252 
  C 7.758 28.682 51.230
basis "ao basis"
  * library 6-311+g*
  bqN library N 6-311+g*
  bqH library H 6-311+g*
  bqO library O 6-311+g*
  bqC library C 6-311+g*
  xc m06-2x
  grid fine
  iterations 10000
  mon first 1 2
  mon second 3 4
task dft energy

However, I'm not being able to replace H atom with a dummy/ghost atom (with no charge) in the calculation.
If I use bqH 5.966 28.410 48.528 in the geometry section and calculate odft then also the calculation an error.
Any suggestions or modification needed in the code to achieve this target will be highly appreciated.
Thank you.

  • $\begingroup$ You should start by just copy-and-pasting the example using their BSSE correction example here. If not, you can just do the BSSE correction by hand by specifying the ghost atoms in the script and giving a task directive below each geometry. $\endgroup$
    – jheindel
    May 8, 2018 at 7:38
  • $\begingroup$ I don't want to do that. I want to calculate the bsse energy of NHOC bond, in absence of H atom. That's why I'm trying to replace it with dummy atom. $\endgroup$
    – diffracteD
    May 11, 2018 at 8:11
  • 1
    $\begingroup$ Using the notation @ for a ghost atom, does this mean you want the BSSE of $\ce{N@H\bond{...}OC}$? That is, keep the hydrogen as a ghost atom during all 5 parts of the BSSE calculation? If so, you may have to do the whole thing "by hand" and piece the BSSE expression together manually, otherwise the program will try and replace a ghost atom with a ghost atom, which is an edge case. $\endgroup$ May 12, 2018 at 16:06
  • 1
    $\begingroup$ Something else that's missing: what do you expect the charge and spin multiplicity to be on each of your fragments? $\endgroup$ May 12, 2018 at 16:07
  • $\begingroup$ Sorry, 3 calculations, not 5. (AB in the basis of AB) - [(A in the basis of AB) + (B in the basis of AB)], all with ghost H. $\endgroup$ May 12, 2018 at 16:27


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