Gaussian4beginners

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If you want to learn how to use Gaussian, please take the files below and follow the instructions. The documents were prepared for the Master on Computational Chemistry and are a guide to develop some simple calculations.

File:General.pdf <- In this document you will find the general instructions to follow.

File:Guions 0809.pdf <- In this document you will find the systems to study.

0.- You may want to make a look at Linux and Unix
1.- Chose some of the reactions to study from the file attached above.
2.- Draw the reactant or product of the reaction with GaussView (all it from kimik as gview; Gauss View)
3.- After drawing them, go to "Calculate" menu and chose "Gaussian". In the menu, chose "Opt+Freq" (Optimization and Frequencies calculations) the "semiempirical" method "AM1". Press on Retain.
4.- Save the files as input files, namefile.in
5.- Send them to the queue; "qs 1 s g03 namefile.in"; KIMIK:
6.- Once finished, check if the geometries correspond to the Reactant and intermediates you wanted.
7.- Get the energies and save them in an Spreadsheet. Compute the difference in energy between reactant and products (be carefull outputs give energies in hartree)
8.- Run single point calculations "b3lyp/6-31g" on the AM1 geometries you optained before. Open the optimized geometries and use them as input for new calculation, chose in the "Calculate" & "Gaussian" menu: "Energies" & "DFT" & "b3lyp" & "6-31G"
9.- Copy the energies on the spreadsheet and compare this energies with the ones obtained with AM1.

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1.- Run reaction coordinate searches between reactants and products for the chosen reactions. That is take the geometry of your reactant or product, thing which is the geometrical parameter that changes the most along the reaction. If the