Molecular Symmetry

Question 1

How do you find the symmetry elements of the vibrational modes?

Answer 1

Sum the x, y and z vectors

multiply each by the number of atoms that lie on the plane

reduce to reducible representation

use reducible representation to find the number of summetry elements in that red rep

Question 2

How do you find the RR of a salc?

Answer 2

Its simply the number of atoms on each symmetry operation

Question 3

How are s and p orbitals handled in terms of symmetry?

Answer 3

s - always A1

p - always directional, x y and z

Question 4

How do you do symmetry stuff for metals

Answer 4

Sigma type interactions first:

1. Find s, p and d orbitals (character table)
2. Find salc for ligands and find IR
3. Combine to make sigma orbitals

Pi type interactions second:

1. Each ligand has p orbitals which need to be treated together
2. add xyz and multiply by no of atoms on symmetry operations to find RR
3. reduce to IR to find pi type orbitals
4. combine to find interactions