(©2009, François G. Amar, All rights reserved)

Chemistry 475 -- Quantum Chemistry & Spectroscopy

Summary for Week 11

Monday, April 6 to Friday, April 10, 2009

Reading in Levine: Chapter 19

Homework problems

Hand in on Monday, April 13: 19.29, 19.30,19.35, 19.36, 20.3, 20.6

Key Concepts

Simple molecular orbital theory for H2 overestimates ionic contribution to bonding

Simple valence bond theory for H2 underestimates ionic contribution to bonding

Diatomic molecule term symbols summarize angular momentum and symmetry information about the

electronic state:

2S+1L Examples are 1S and 2P

Selection rules for diatomics:

ΔS=0 ΔL=0,±1 for Hund's cases a) and b). Some additional restrictions based on parity.

Beer-Lambert law

Absorption and emission of radiation for a two-state system; Einstein coefficients

Dipole selection rules

Using the harmonic oscillator and rigid-rotor models to interpret the rovibrational spectral of diatomic molecules.

Rovibronic spectra

 

 

 

 

 

 

 

 

 

 

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