Excited State Structural Dynamics of the Charge Transfer State of Peridinin

摘要

We present infrared and visible transient absorption measurements of the first excited singlet state(S1 and S_(1/ICT))of peridinin in methanol,isopropanol,and chloroform solution following one-photon excitation,using 490 nm light,to excite the S2 state that populates S1 via rapid(~50 fs in methanol)internal conversion.This technique enables the study of subsequent structural dynamics in S1 involved in the formation of the charge transfer state.The S1 lifetime of peridinin in methanol,isopropanol,and chloroform is found to be 12,54,and 65 ps,respectively,as determined by infrared transient absorption.We observe two formation timescales in the S1 state.We attribute the shortest timescale to relaxation following internal conversion and the longer timescale to formation of the S_(1/ICT)state.