Sincerely yours,
Saeed

I suggest try to use ELF or LOL isosurface.

To represent hole by isosurface of Laplacian of rho, the precondition is that Laplacian of rho is able to exhibit the region where electron density concentrates (e.g. lone pair and covalently bonding regions), but it often fails for elements with large atomic radius, such as Sn.

Best,

Tian

Please, also, let me ask one more question. In some cases, such as for TeHF compound in which the presence of a sigma-hole along the extension of the Te-F bond is expected, drawing isosurface of Laplacian of Rho (with isovalue= 0, namely the reactive surface) does not show a hole. On the other hand, this sigma-hole can be seen when isovalue is increased to 0.001 (a value slightly greater than zero). Could you please let me know why?

As another case, SnH3F could be mentioned. For this compound, the emergence of an expected hole along the Sn-F bond can never be satisfied using ANY value as isosurface for Laplacian of Rho. Such cases made me quite confused. Please let me know why some cases fail to present an expected sigma-hole over the Laplacian isosurface. I tried several times to attach "SnH3F.fch" file generated at M06-2X-D3(0)/def2-TZVPP level but, all tries failed! Using Multiwfn and VMD, I could not see the sigma-hole in this compound at any isovalue of Laplacian of Rho!

Sincerely,
Saeed

I think it is true.

Best,

Tian

In advance, thank you very much.

Sincerely,
Saeed