Theory 02/Ultrafast/Molecular coherence
Coherence Lasts a Vibration
The claim
Electronic coherence in molecules survives only while the ratio of vibrational period to electronic decay time is large, so coherence is lost when nuclear motion outpaces the electronic dephasing.
01Mechanism
Nuclear motion modulates the electronic energy; when the vibration is fast relative to decay, the phase is scrambled before the coherence can be used.
02Prediction
Coherence time should track the ratio.
03Refutation
Coherence tracking decay time alone would remove vibration.