MO Calculations on PC

Dr. Christoph UP, April 2015

http://www.arguslab.com/ arguslab.com/ArgusLab.html

Step 1: Construct a molecule by dropping atoms on the screen (“Builder Tool”)

Step 2: Define atoms by right-click on them

Step 3: Optimize geometry

Step 4: Calculate HOMO and LUMO surface

Step 5: Calculate MO energies

Exercises Construct the O2 molecule and get HOMO and LUMO

We should use PM3 as method, not AM1

Because of the diradical character most QM methods do not work here ! Only EHT as very crude method.

H2O Here it is enough just to put an sp3 O atom and then choose “add Hydrogens”

Mark 2 atoms: left click and ctrl-left click Then display the distance:

HOMO and LUMO “Quick Plot”

The LUMO looks very confusing in standard view

Right Click on the surface around the Hydrogens

Modify surface -> choose Mesh display We see now that the LUMO is actually a lone pair !

Interaction between Imine and ZnO

Mark all atoms of one group (CTRL-left click) and select: Make a group…

Group 1: Binding Site

Group 2: Ligand

“Docking” Ligand to binding site

Calculation suggests that the imine double bond is perpendicular to the Zn-O axis, actually like “inserted” into the Zn-O bond