Ultrafast dynamics of chlorobenzene clusters

The ultrafast dynamics of chlorobenzene clusters upon 271 nm excitation is studied by femtosecond pump–probe time-of-flight mass spectrometry. Transient profiles of clusters are fitted by two-exponential decay component models, an ultrafast component and a slow decay component. The ultrafast (∼170 fs) decay of S1 state is tentatively attributed to the internal conversion to the high vibrational levels of S0 state. Lifetimes of this ultrafast component decease with the cluster size, due to the influence of the solvation effects, while lifetimes of the slow decay component (>1 ns) increase with the cluster size, due to the increase of freedom degrees.