Broad-Band Pump-Probe Spectroscopy Quantifies Ultrafast Solvation Dynamics of Proteins and Molecules.

摘要: In this work, we demonstrate the use of broad-band pump–probe spectroscopy to measure femtosecond solvation dynamics. We report studies a rhodamine dye in methanol and cryptophyte algae light-harvesting proteins aqueous suspension. Broad-band impulsive excitation generates vibrational wavepacket that oscillates on excited-state potential energy surface, destructively interfering with itself at minimum surface. This destructive interference gives rise node certain probe wavelength varies time. reveals Gibbs free-energy changes which equates time correlation function. method captures inertial solvent response water (∼40 fs) bimodal ∼150 how protein-buried chromophores are sensitive dynamics inside outside protein environment.