Table 2.

Summary of typical process times from excitation to emission.

Transition Example	Process	Rate	Typical Timescale
So → S1	Excitation, Absorption	k(e)	Femtoseconds, 10−15 s
	Internal Conversion	k(ic)	Picoseconds, 10−12 s
	Vibrational Relaxation	k(vr)	Picoseconds, 10−12 s
S1 → S0 (radiative)	Florescence	k(f)	Typically less than 10−8 s
S1 → S0 (non radiative)	Quenching and other non radiative processes	k(nr), k(q)	10−7 – 10−5 s
S1 → T1	Intersystem Crossing	k(pt)	10−10 – 10−8 s
T1 → S0	Phosphorescence	k(p)	10−3 – 100 s (earlier literature) > 10−8 s (recent literature)