# Possible to Calculate Electronic Charge Distributions/Densities for Organic Molecules?

I was wondering if there are any programs that can calculate the electronic charge distributions around an organic molecule, possibly in the form of a volumetric charge volume density? I am reading up about using DFT programs that (correct me if I'm wrong) I believe may be able to tell us something about finding the charge density.

I'm working on a project that involves obtaining the electric field values surrounding an organic molecule. My current approach involves finding a function for the molecule's electronic volume charge density and doing a volume integral to get the electric field.

Is this a potentially valid method? If not, what else should I look into?

• Even I'm searching for it.
– Uday
Feb 12, 2018 at 0:41
• It's possible to calculate the electrostatic potential at points around a molecule. Is that what you're after? Feb 12, 2018 at 17:05
• The problems is that programs let alone do very little. Yes they do exist and for sure there are specialists or chemists knowing enouggh to help, here. . Feb 12, 2018 at 19:38
• Every DFT program computes the electronic density, i.e., the negative charge density due to electrons. The positive charge density is a sum of Dirac distributions over $\mathbb{R}^3$ given by the nuclear positions and their charges. Are you looking for the electrostatic potential? If you have Gaussian and molden, you can visualize the electronic density and ESP given the right input. Feb 12, 2018 at 20:55
• It is not clear what you want to analyze, so you may want to check out electrostatic potential maps: chem.libretexts.org/Core/Physical_and_Theoretical_Chemistry/…
– Greg
Feb 13, 2018 at 10:44

If I understand correctly, you want the total electric field at some point $\mathbf{r}$ due to a molecule. This will have at least three components. The first due to the electric field from the nuclei. This can be calculated classically from the field due to point charges. The second due to the dipole moment of a molecule. This can also be calculated completely classically (though you will have to use some electronic structure calculation to get the dipole and direction). Finally, you will need to find the total charge density of the electrons.