Multiwfn forum

SCmwfnQ

Member

Registered: 2022-09-04

Posts: 2

Electron density cube file from UHF Molden file for alpha spin only?

Dear Tian Lu,
Can Multiwfn generate a cube file from alpha spins only (or beta spins only) from a UHF molden file?
I've been using orbkit to do that, but Multiwfn has a lot of advantage!
Thanks very much,
Steve Coy

sobereva

Tian Lu (Multiwfn developer)

From: Beijing

Registered: 2017-09-11

Posts: 1,763

Website

Re: Electron density cube file from UHF Molden file for alpha spin only?

Dear Steve Coy,

It is quite easy. Subfunction 26 of main function 6 can manually modify occupation numbers of various orbitals. In this function, input indices of beta orbitals first, and then input 0 to set their occupancy to zero, then return to main menu. After that, if you calculate electron density as usual, then the result will correspond to alpha density only. Main function 5 can compute grid data of a selected real space function and export a cube file.

Note that the index ranges of alpha and beta orbitals are automatically shown on screen after loading an unrestrricted wavefunction.

Best regards,

Tian

sobereva

Tian Lu (Multiwfn developer)

From: Beijing

Registered: 2017-09-11

Posts: 1,763

Website

Re: Electron density cube file from UHF Molden file for alpha spin only?

I forgot to say, there is an even easier way without manually modifying orbital occupancy.

As you can see from Section 2.7 of Multiwfn manual, user-defined functions 1 and 2 correspond to alpha and beta densities, respectively. Therefore, assume that you want to generate cube of alpha density, you just need to set "iuserfunc" in settings.ini to 1. After booting up Multiwfn and load wavefunction file, enter main function 5. Then when Multiwfn asks you to choose the real space function, select "100 User-defined function", then alpha density will be calculated, and you can export cube file in post-process menu.