Absorption and
Emission
Two most interesting
and most useful processes when EM interacts with matter
Atoms and molecules
can exist in many possible energy states
Consider two states
E
Absorption
Emission
State 1
Ground State
State 2
Excited State
For absorption of EM
DE = E2 – E1 = hn
Where E1 & E2 are
energies of states &
h is Planck’s constant
n is the frequency