Which method? • We’re using Density Functional Theory (DFT) as it gives us the

most accurate results for transition metals in the least amount of time. We’re using the B3LYP flavor of DFT as it is the most common one.

Which basis set?  Basis sets are approximations of atomic orbitals • We will be using LANL2DZ for our calculation as it models the

bonding in transition metal complexes well.

What job type?• Geometry Optimize + Vibrational Frequencies (for reactants or

products)

We are calculating points on the Potential Energy Surface (PES): Energy and other properties are a function of geometry

  Local maxima

Saddle Point

Maxima and Minima are stationary points (1st derivative of PES =0)• Minima gives equilibrium structure(s) of reactant or product;

must have NO imaginary frequencies• Saddle point corresponds to transition structure; transition

states should have ONE imaginary frequency

Input Initial Guess

Input Initial Guess

Gaussian calculates Integrals

Gaussian calculates Integrals

Stationary Point

reached?

Stationary Point

reached?

You’re Done!You’re Done!

New Geometry

Guess

New Geometry

Guess

YES

NO

Item Value Threshold Converged? Maximum Force 0.000005 0.000450 YES RMS Force 0.000002 0.000300 YES Maximum Displacement 0.000012 0.001800 YES RMS Displacement 0.000006 0.001200 YES Predicted change in Energy=-1.586489D-10 Optimization completed. -- Stationary point found.

Geometry Optimized? Should see something like:

\NImag=0\

Is it a minima? Search for NImag (Should be 0 for minima)

Zero-point vibrational energy 53572.7 (Joules/Mol)

12.80419 (Kcal/Mol) … Thermal correction to Gibbs Free Energy= -0.006541 Sum of electronic and zero-point Energies= -997.086339 Sum of electronic and thermal Energies= -997.080515 Sum of electronic and thermal Enthalpies= -997.079571 Sum of electronic and thermal Free Energies= -997.113285

Want thermochem data? Search raw output for Kcal

Anything else? Click on the magnifying class to the right of your job in WebMO

Bohr: Atomic unit of Length (a0)o Equal to the radius of the first Bohr orbit for a hydrogen

atomo 5.29 x 10-11 m (0.0529 nm, 52.9 pm, 0.529 Å)

 Hartree: Atomic unit of Energy

o  Equal to twice the energy of a ground state hydrogen atom 627.51 kcal/mole 2625.5 kJ/mole 27.211 eV 219474.6 cm-1