gaussview and gaussian tutorial for
Launch GaussView. Initially two or three windows will be displayed:
the main window, a blue or purple View window, and possibly a small GaussView Tips window.
Open the Builder window by selecting Builder in the main-window View menu.
Build a molecule of toluene.
This toluene description and the suggestions follow Taras Pogorelov's
- Start a new molecule from the Main window:
File→New→Create Molecule Group.
- In the Builder window, click the ring button. (It looks like benzene.)
The Ring Fragments window will appear.
- Select benzene (the top left button) and it appears in the main window.
Note that the main window's Builder Fragment button
also displays "benzene."
Click anywhere in the View window and benzene will be added
to the View window.
Should you want to move (translate) the benzene molecule
in the View window, hold down the shift
key while dragging with the left mouse button.
- Click on the Element button (it displays 6C)
on the Builder panel.
The "Elements Fragments" panel will appear.
Select Carbon and Tetrahedral.
CH4 will appear in the main window.
The C atom of CH4 is colored
light blue, indicating that it is the "hot" atom.
In the View window,
click on any H atom; it will be changed to CH3,
- Use molecular-mechanics energy minimization to quickly,
albeit approximately, improve toluene's geometry:
In the Builder panel, click the Clean button (the broom icon).
GaussView will run a classical-mechanical energy optimization
of the toluene structure in the View window.
- Save the toluene molecule as toluene.com.
- Change toluene to phenol by replacing the CH3
group with OH. This can be done as follows: Open Builder's
Element Fragments window, select O and "tetravalent."
Water with the O atom "hot"
will appear in the main window.
Then in the View window click on the methyl C atom.
It will be replaced with OH.
- Let us try to convert phenol to the phenoxide anion.
To do this, delete the
H atom that is attached to the O atom, as follows.
On the Builder menu, the atom deletion tool has the icon
. After selecting the
atom-deletion tool, click on the H atom to be removed, in the
View window. Then save the C6OH5
molecular fragment as "phenoxide.gif". (In this
context, "gif" stands for Gaussian input file.)
Changing the molecular charge from 0 (for the radical)
to -1 (for the anion) cannot be done at the
molecular-drawing or clean-up stage.
Rather, charge is set when preparing to run
a quantum-mechanical calculation, as follows:
- In the main window, choose
"Gaussian Calculation Setup"
from the Calculate menu.
- Click on the Method tab. Type -1 in the
If one clicks on any other tab (e.g., the Title tab)
the View window updates, showing the new -1 charge.
- Clicking on Submit will run a Gaussian calculation
on the phenoxide anion. (Gaussview will first prompt
for re-saving the Gaussian input file, which one
This part of the tutorial uses diatomic molecules to try out
computational methods, basis-set selection, and spin specification.
Clicking New in the main-window File menu will create a new View window.
- Use double-bonded O from
Builder's Element Fragments window to
- Save the O2 molecule as a Gaussian input file.
- Open the Gaussian Calculations Setup window from the
main window's Calculate menu. The following choices will
set up a triplet-state geometry optimization using
density functional theory and the 6-31g(d) basis set.
|tab ||box ||value |
|Job Type || ||Optimization|
||DFT Unrestricted B3LYP|
||Basis Set ||6-31G (d ) |
- Submit the calculation.
- When the calculation is complete, GaussView will suggest
opening the results (the "chk" file). Do open it.
In the main window, click on the Results menu and select
- Use the Builder window's Inquire button (
measure the O=O bond length.
It should be 1.214 Angstroms.
- Repeat the O2 calculation for the singlet state.
The only setting to change is the Spin, from triplet to singlet.
The calculation results should show that
the singlet bond length is 1.216 Angstroms and
the total energy (Results Summary window)
is -150.2574 au. The energy unit "au" stands for
the atomic unit of energy, which is Hartrees.
The singlet lies (-150.2574 - - 150.3200)
= 0.0626 Hartree = 1.7 eV above the triplet, at this
level of theory.
- Create a CO molecule in the View window. Save it.
- Set up a Gaussian calculation that will optimize
the bond length and calculate the vibration frequency.
|tab ||box ||value |
|Job Type || ||Opt+Freq|
||Basis Set ||6-31G (2d) |
- Submit the job.
- The Results summary will show total energy = -113.05314 au.
The bond length is 1.144 Angsroms.
- Selecting Vibrations from the main-window Results menu
will calculate and then display the vibration frequency,
plus a calculated IR spectrum.
- Create a nitrogen molecule in the View window.
Run Builder's Clean. The bond length will be 1.092 Angstroms.
Save the N2 molecule..
- Set up a Gaussian calculation using the defaults.
|tab ||box ||value |
|Job Type || ||Energy|
||Basis Set ||3-21G |
- Submit the job. After it finishes, accept GaussView's
offer to open the output chk file.
- The Results summary will show total energy = -108.3007 Hartree.
- To view molecular orbitals, choose Surfaces/Contours from
the main-window Results menu.
The Surfaces and Contours window will open, but will not
list any available surfaces.
Begin by generating "cube" files for the
HOMO and LUMO.
Choosing Cube Actions / New Cube
will open the Generate Cube window.
In the Generate Cube window, choose
Type: Molecular Orbital
Orbitals: HOMO (orbital number 7)
and Click OK. MO 7, the HOMO, will be added to the
list of available cubes.
Also create the cube for the LUMO, MO 8.
Go to the Surfaces and Contours Window.
Select (click on) the MO 7 cube.
Then choose Surface Actions / New Surface.
MO 7 will appear in the Surfaces Available list
and will appear in the View window.
MO8, the LUMO, can be displayed by first hiding MO 7
and then choosing New Surface for MO 8.
building larger molecules
Work the Gaussview tutorials "Building Pyridine" and
These tutorials may be accessed through the GaussView
Help menu. (Help/GaussView Help/Tutorials)
page contact: psiders"at"d.umn.edu