Multiwfn forum / Integrating grid data in cube in whole space

Re: Integrating grid data in cube in whole space

dummy@example.com (sobereva) — Tue, 07 Jul 2026 22:05:49 +0000

Hello,

In Multiwfn, all indices, including orbital indices, always starts from 1 (PS: I quite dislike starting from 0)

Re: Integrating grid data in cube in whole space

dummy@example.com (Hengyuan) — Tue, 07 Jul 2026 20:31:40 +0000

I found the exact functionality I wanted in the manual 3.100.11 Calculate overlap and centroid distance between two orbitals. However, does the orbital index start with 0 or 1? As 0,0 is the exit code, I would assume the orbital index start with 1?

Integrating grid data in cube in whole space

dummy@example.com (Hengyuan) — Tue, 07 Jul 2026 20:09:13 +0000

Dear Tian,

I tried to calculate the overlap between HOMO density and LUMO density from an orca gbw file, and I am using Multiwfn version 3.8, update date 2026-Jan-7. I saved the orbital probability densities in cube files, and multiplied them together through the multiplication in Grid data calculation. However, I couldn't find the integration option for grid data, could you please elaborate on this? Thank you.

Best,
Hengyuan