EXAM 2

A
A = symmetric to principle rotation
B
B = antisymmetric
E
E = 2 dimensions
T
T = 3 dimensions
Subscripts
1 = symmetric to C2’s or ?v (if no C2)
2 = antisymmetric .
g and u
g = symmetric to
inversion, u = antisymmetric.
Rx, Ry, Rz
Are used to match orbitals, e.g. x with
+ve and –ve directions matches px, xy with alternating signs in quadrants matches dxy.Rotational functions describe rotations, other motions of molecule.
Vibrational modes
a molecular vibration is infrared active if a vibration changes the dipole moment. 3N-6
point lattice
a set of points arranged so that each point has identical surroundings. In addition, a point lattice can be characterized in terms of three spatial dimensions: a, b, and c and three angles, alpha, beta and gamma. The lengths and angles are known as lattice parameters or unit cell parameters and a single cell constructed using these parameters is called the unit cell