Rendering molecular orbital on Jupyter notebook #psikit #py3dmol #rdkit #memo

@fmkz___ and I( @iwatobipen ) are developing psikit which is a thin wrapper of psi4 and rdkit. I hope the package integrates quantum chemistry (Psi4) and chemoinformatics (RDKit).

By using psikit, user can make molecular orbital data very convinienlry.

Rendering MO is useful for understanding molecular electrostatic shape and nature, but sometime it is difficult to medicinal chemist because it requires CADD skills for rendering it.

Psikit has useful method named ‘create_cube_files’, the method make cube files of HOMO, LUMO and ESP. And also psikit can call pymol to rendering them. However it can’t render MO directory on jupyter notebook so I would like to show you how to render MO on jupyter notebook today.

Fortunately, py3Dmol is easy tool for rendering CUBE file!

Sample code is below. I used psikit for quantum calculation and used py3dmol for rendering. First, calculate energy and create cube files. Default gridspace value is set 0.3 but I recommend it should be changed more large r value. Because cube file with small gridspace value will become huge size file.

import py3Dmol
from psikit import Psikit
from rdkit import Chem
pk = Psikit()

After running the method, cube files are generated. So read the file.

homo_voldata = open("Psi_a_5_1-A\"_HOMO.cube", "r").read()
lumo_voldata = open("Psi_a_6_5-A\'_LUMO.cube", "r").read()

Now ready to render. Make view object and attach some dataset. addVolumetricData method loads cube data with options. Then call addModel with molblock data. RDKit can convert molobject to molblock by using MolToMolBlock method.

v = py3Dmol.view()
v.addVolumetricData(homo_voldata, "cube", {'isoval': -0.03, 'color': "red", 'opacity': 0.75})
v.addVolumetricData(homo_voldata, "cube", {'isoval': 0.03, 'color': "blue", 'opacity': 0.75})
v.addModel(Chem.MolToMolBlock(pk.mol), 'mol')

Works fine. The molecule object is rotatable. LUMO can be rendered with same manner.

In summary, psi4, rdkit and py3dmol integration can render molecule with MO at the touch of a button. I uploaded today’s code on my repository.

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view raw RenderMO.ipynb hosted with ❤ by GitHub

Published by iwatobipen

I'm medicinal chemist in mid size of pharmaceutical company. I love chemoinfo, cording, organic synthesis, my family.

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