Basis set superposition error correction

[sonal AGRAWAL]

Dear sir,
Is basis set superposition error correction i.e. counterpoise correction is necessary in sensing of molecules on a sheet. is this error cause large variation from the experimental results as given in the manual of counterpoise correction or we may consider only vanderwall interaction and ignore counterpoise correction.

[Troels-Markussen]

Hi,

It is difficult to answer this question very generally. But sometimes basis set superposition errors (BSSE) can be significant leading to an overbinding, i.e. too large binding energy. If you get very different binding energies with and without the Counterpoise correction, it is probably important. In order to address the problem for a particular case, I would suggest that you try to compare your results with plane-wave calculations, using the PlaneWaveCalculator, since this does not suffer from BSSE.

Regards,
Troels