Bader charges for symmetric molecules
Posted: Mon Jan 13, 2014 3:44 pm
I have been using the Bader algorithm for the calculation of atomic charges on simple organic molecules through Gaussian09. While calculating the Bader charges, I came across a strange result.
For example, in the case of simple pyridine, the Bader charges on the two (chemically identical) C atoms in alfa-position with respect to N are markedly different (+1.27 and +1.16). This has no chemical meaning! The same also occurs on acridine: +1.43 and +1.47.
Does anyone know why it is like this? Do you know how to fix it? My Gaussian optimization was performed with DFT, with B3LYP functional and 6-31G** basis set. Dispersion effects (Grimme) have been introduced in the calculation via the IOpt(3/124=30) keyword.
Thank you in advance. Regards.
Andrea.
For example, in the case of simple pyridine, the Bader charges on the two (chemically identical) C atoms in alfa-position with respect to N are markedly different (+1.27 and +1.16). This has no chemical meaning! The same also occurs on acridine: +1.43 and +1.47.
Does anyone know why it is like this? Do you know how to fix it? My Gaussian optimization was performed with DFT, with B3LYP functional and 6-31G** basis set. Dispersion effects (Grimme) have been introduced in the calculation via the IOpt(3/124=30) keyword.
Thank you in advance. Regards.
Andrea.