The bonding or antibonding interactions can be calculated withe the QTAIM method (AIMAll package, for example) through the Gaussian checkpoint file (generate chk file by the commands %chk=name.chk and guess=save). Only Bader's QTAIM metod can provides the strict criterion of the bond presence. See attachment, for example ("The AIM theory: fundamentals and applications" section on P. 1255).
Thank you for your reference. I will let you know if there is any difficulties.
Perhaps you just want the interaction energy? Use a big basis with diffuse functions, dispersion and the couterpoise technique. In Gaussian, couterpoise cant be done with solvent I believe so you may need to decide which is more important, the solvent effects of the BSSE.
Dear Chanchal Haldar,
Go through through the reference. you can find the non-bonding interactions through NBO analysis. I hope you get an idea from the reference.
All the best
Dear Chanchal Haldar,
Do you mean interaction energies?!!. if yes, you should use counterpoise=n keyword where n is the number of interacting systems. for instance you want to calculate He...He interactions. the input is similar to:
# method/basis set counterpoise=2
He x y z 1
He x' y' z 2
you should put 1 in front of coordinates of atoms which belong to monomerA (of course with one space distance) and 2 for monomerB. In addition, if you want to use density functional, and your system is middle size, aug-cc-pvtz is enough, because DFT is a effective potential method and converges with basis set quickly, you do not need use too large basis set. Also, QTAIM is good for showing the existence and nature of interactions qualitatively, but sometimes, it dose not show any critical point, so you are enforced to use complicated topological justification!.
Thank you Yourdkhani. I will let you know after following your steps.
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