# MultiWFN

## Electron Density Difference - Contour Plot¶

Load in the fchk file (if using psi4, be sure to generate the wfn for this with reference UHF, as MultiWFN requires $$\alpha$$ and $$\beta$$ orbitals)

1. 4 - Plot plane map
2. 2 - Tell Multiwfn you want to draw deformation map

3. Specify your level of theory for calculating the electron density. ENTER for B3LYP/6-31G*

4. 1 - Electron density function

5. 2 To generate a contour map

6. Specify your resolution. Press ENTER for 200x200

7. Choose how you’d like to align the plane the contour should be measured across.

## AIM - Calculating basin volume (for polarisibility)¶

AIM - Calculating basin volume

1. generate .wfn with orca_2aim baename
2. load in .wfn with multiwfn basename.wfn
3. 17 - Basin analysis
4. 1 - Generate basins and locate attractors
5. 1 - Electron density
6. 2 - Medium quality grid
7. 7 - Integrate real space functions in AIM basins with mixed type of grids
8. 2 - Integrate a specific function with atomic-center + uniform grids, but with exact refinement of basin boundary
9. 1 - Electron density