Electrostatic Potential Map

1

Hello! I am new to Psi4 and I am trying to generate an electrostatic potential map. I’ve started with the following input.dat

molecule h2o {
0 1
O
H 1 1.0
H 1 1.0 2 104.5
}

set basis cc-pvdz
set scf_type df
set df_basis_scf cc-pvdz
set freeze_core True
set cubeprop_tasks ['esp']
#set cubeprop_orbitals [5,6,-5,-6]

E, wfn = energy('scf', return_wfn=True)
cubeprop(wfn)

When I load the .cube file in VMD all I get is a single color red water molecule surface. There is no gradient. I do not see any errors in the output file. I am not sure if I got the df_basis_scf right which the manual says must be set. Thanks!

2

I’ve not used the electrostatic potential generation functionality myself. Regarding the df_basis_scf, if you set it explicitly, it should be something ending in jkfit, so probably cc-pvdz-jkfit as from http://psicode.org/psi4manual/master/basissets_byfamily.html . An auxiliary basis the same size as the orbital basis, as at present, would definitely give a bad answer.

3

Thanks for the clarification there. I’ve made that change, but still no luck. I’ve also tried using the vmd_cube.py script which generates the same solid color I get if I load the .cube manually. I’ve been combing through the examples to see if one is in there, but no luck yet…

4

Usually you want to have a density and colour a certain isovalue of it with the ESP (i.e. loading 2 cube files)
If you just plot the esp at a given isovalue, you will just get a single color.