Direct Observation of Ultrafast Dissociation Dynamics of (R–I)n-Type Iodide Clusters as a Result of UV Excitation below the Ionization Threshold

Abstract

The dynamics of dissociation of (IF₂CCOF)_n, (CF₃I)_n, and (CH₃I)_n clusters induced by femtosecond UV radiation (λ = 266 nm) is investigated. The method of UV excitation and photoionization probing (λ = 400 nm) combined with the time-of-flight mass spectrometry is applied. It is found that clusters excited to Rydberg states lying below the ionization threshold are decomposed, as a result of subsequent relaxation processes, giving rise to free neutral molecules. A mechanism of electronic–vibrational relaxation process is proposed, and data on the characteristic times of different stages of this process are obtained.