Aurelie's C3H6 page...
The aim of this tutorial is to learn some things about Gaussian, and at the end to be able to use Gaussian to make the appropriate calculations, and to have a good understanding of the results.
For this we are going to study two molecules : the propene and the cyclopropane.
First we are going to calculate the energie of these molecules, then we will try to do an optimization of geometry, then we will look at the NMR spectra of these molecules. And in the fifth part we will take an interest in the frequencies calculations.
And finally we are going to propose some transition state between the two molecules.
Calculate the energy with the Hartree Fock theory
Calculate the energy with the DFT
Where is the energy of the molecule in the file .log ?
Are these calculations usefull?
Direct applications
Stability of a structure ?
Singulet or Triplet ?
The other informations
Dipole and higher multipole moments
Charge distribution
Molecular orbitals and orbital energies
Calculations with HF and the DFT
What can you see in the file .log ?
Transition state optimization
Calculations
What can you find on the file .log ?
Frequencies and intensities
Thermochemistry
Normal mode
Imaginary frequency
What does it correspond to ?
What are the differents situations ?
Characterizing stationary points
Optimization + frequencies calculations
Animated frequencies
Our propene
Moeller-Plesset Perturbation Theory
Coupled Cluster Singles and Doubles model (CCSD)
Molecular Mechanics (MM)
Semi-empirical methods
The Born-Oppenheimer approximation
Potential Energy Surface (PES)
