Theory 07/Photochemistry
Quantum Yield Is a Race
The claim
Photochemical quantum yield is set by the ratio of excited-state lifetime to vibrational relaxation time rather than by absorption cross-section.
01The mechanism
A reaction competes with relaxation; the ratio determines what fraction of excited molecules survive long enough to react.
02Predictions
- P1Yield should track the ratio.
- P2Stronger absorption should not raise yield.
03Refutation
Yield tracking absorption would remove the kinetic competition.