Spectroscopy Flashcards
Transition between electronic energy levels involves
UV/Vis radiation
Transition between vibrational energy states involves
Infrared radtiation
Transition between rotational energy levels involves
Microwave radiation
UV/Vis representative frequency
10^15 Hz
Infrared representative frequency
10^14 Hz
Microwave representative frequency
10^11 Hz
UV/Vis representative wavelength
Hundreds of nm
Infrared representative wavelength
um range
Microwave representative wavelength
mm range
Direct electric dipole transitions are a result of
Interaction with EM radiation that is resonant with the separation between energy levels
Ratio of degeneracies of electronic energy levels v=0 : v=1
1:1
Ratio of degeneracies of vibrational energy levels v=0 : v=1
1:1
Ratio of degeneracies of rotational energy levels v=0 : v=1
1:3
Name the three processes given by the Einstein Model
Absorption, spontaneous emission, induced emission
Absorption reaction equation
X + hv -> X*
Spontaneous emission reaction equation
X* -> X + hv
Induced emission reaction equation
X* + hv -> X + 2hv
The rate of a transition process depends on
- number of molecules in the initial state
- rate coefficient of the transition
- spectral radiation density
Define spectral radiation density
Concentration of photons interacting with matter
Define transition moment
Size and direction of the transient change in the oscillating dipole moment accompanying the transition between two states
What is the relationship between M and B, why is it important?
B = |M|^2
Shows that the transition moment is proportional to the probability of a transition occurring
When is a transition allowed?
When M>0
When is a transition forbidden?
When M=0
