Multiwfn forum

saeed_E

Member

Registered: 2019-12-21

Posts: 319

surface charge density

Dear Tian,
Hi, I hope you are doing well.
Suppose I want to determine the surface charge density for the sodium atom in a compound like NaOH. In other words, I’d like to calculate the amount of electric charge per unit surface area on the sodium atom. Could you please let me know how this can be achieved using Multiwfn in a clear and step-by-step explanation?

Sincerely yours,
Saeed

sobereva

Tian Lu (Multiwfn developer)

From: Beijing

Registered: 2017-09-11

Posts: 2,055

Website

Re: surface charge density

"amount of electric charge per unit surface area" is not well-defined. If one uses isosurface of electron density to define the surface, then electron density is the same everywhere on the surface. Statistics information of ESP over the surface is more meaningful and well-defined.

saeed_E

Member

Registered: 2019-12-21

Posts: 319

Re: surface charge density

Thanks a lot.
Could you please make your meaning more evident?
For example, it is said that the surface charge density of atoms X in compound XY is "a" e/squar Angstrom. How is the value of "a" determined?

Saeed

sobereva

Tian Lu (Multiwfn developer)

From: Beijing

Registered: 2017-09-11

Posts: 2,055

Website

Re: surface charge density

As I noted earlier, this depends on how the surface is defined. If it is defined as isosurface of electron density, then "a" will be a constant for all atoms and all molecules, making the discussion completely meaningless.

saeed_E

Member

Registered: 2019-12-21

Posts: 319

Re: surface charge density

Thank you.