Multiwfn forum

mdelarmelina

Member

Registered: 2023-09-12

Posts: 1

MO, atoms, and basis function contributions to h-e distribution

Dear all,

Recently, I have started running some simple tests with Multiwfn 3.8 to analyse hole-electrons formation in small gold clusters. I run default TD-DFT (TDA) calculations on Orca 5.03 and these inicial tests used B3LYP functional in combination with LANL2DZ. I am mainly interested in MO, atoms, and basis function contributions to hole-electrons distribution. However, for some of the contributions given by Multiwfn 3.8, I get negative percentages. For example:

Using atom contribution from Mulliken method:
Contribution of each non-hydrogen atom to hole and electron:
1(Au) Hole: 6.66 % Electron: 1.59 % Overlap: 3.26 % Diff.: -5.07 %
2(Au) Hole: 1.89 % Electron: -0.46 % Overlap: 0.00 % Diff.: -2.36 %
3(Au) Hole: 2.73 % Electron: 2.12 % Overlap: 2.41 % Diff.: -0.61 %
4(Au) Hole: -7.83 % Electron: 0.51 % Overlap: 0.00 % Diff.: 8.34 %
5(Au) Hole: 5.14 % Electron: 7.69 % Overlap: 6.29 % Diff.: 2.55 %

Or for basis function contributions:
Sum of hole contributions: 0.921316
Sum of electron contributions: 0.921316

Basis Type Atom Shell Hole Electron Overlap Diff.
3 S 1(Au) 3 2.15 % 0.21 % 0.67 % -1.94 %
11 Y 1(Au) 6 1.04 % 0.03 % 0.18 % -1.01 %
34 Z 2(Au) 14 -1.29 % -0.02 % 0.00 % 1.27 %
55 Y 3(Au) 22 0.11 % 1.12 % 0.35 % 1.01 %
76 X 4(Au) 30 -0.72 % -1.77 % 0.00 % -1.05 %
77 Y 4(Au) 30 -6.11 % -0.10 % 0.00 % 6.01 %

I was wondering what could be the origin of this negative percentages and if this could indicate a problem with my TD-DFT calculation. Would this indicate that other contributions that are all positive (atom contribution from Hirshfeld partition method and MO contributions) could be wrong?

Many thanks,
Maicon

sobereva

Tian Lu (Multiwfn developer)

From: Beijing

Registered: 2017-09-11

Posts: 1,768

Website

Re: MO, atoms, and basis function contributions to h-e distribution

Dear Maicon,

The negative value comes from the known theoretical deficiency of Mulliken population. If you are only interested in atomic contribution, I suggest using Hirshfeld method to evaluate the composition instead, Hirshfeld method is much more robust and the result is always nonnegative.

Best,

Tian