© 2002 J.Paul Robinson, Purdue University
Lifetime
•Absorption associated with electronic transitions (electrons changing states) occurs in about 1 femptosecond (10-15 s)
•The lifetime of a molecule depends on how the molecule disposes of the extra energy
•Because of the uncertainty principle, the more rapidly the energy is changing, the less precisely we can define the energy
•So, long-lifetime-excited-states have narrow absorption
peaks, and short-lifetime-excited-states have
broad absorption peaks
3rd Ed.Shapiro p 85
