The experimental setup has been described
in detail elsewhere.21 Briefly, the pump laser pulse with 7 ns
duration at 532 nm was supplied by a Nd:YAG laser operated at a
repetition rate of 10 Hz (Quanta-Ray Pro-Series, Spectra Physics Lasers
Inc., Mountain View, CA), and the pulse energy to excite the sample
was ∼5.0 mJ. β-Carotene