Investigation on the vibrational relaxation and ultrafast electronic dynamics of S1 state in 2,4-difluoroanisole

• Published in: The Journal of chemical physics 2024-09, Vol.161 (12)
• Main Authors: Cao, Ling, Wang, Yanmei, Lu, Xin, Zhang, Song
• Format: Article
• Language: English
• Subjects: Atomic energy levels; Dissipation factor; Photoelectrons; Rydberg states; Spectrum analysis
• ISSN: 0021-9606; 1089-7690; 1089-7690
• DOI: 10.1063/5.0231264

Intramolecular vibrational energy redistribution (IVR) has a profound impact on dynamic processes. We have studied two types of IVR processes, restricted and dissipative, and ultrafast dynamics of the S1 state of 2,4-difluoroanisole using time-resolved photoelectron spectroscopy and time-of-flight mass spectroscopy. The restricted IVR occurs in the intermediate regime of 219 cm−1 vibrational level, and the dissipative IVR occurs in the statistical regime of 1200 cm−1. The lifetimes of IVR processes are measured to be 90 and 11 ps, respectively, depending on the internal energies of the S1 state and differ by a factor of eight. Similar subsequent dynamics were observed at two vibrational levels in the S1 state. The population undergoes IVR following the initial excitation and subsequently leaks into a triplet state, accompanied by intersystem crossing within ∼400 ps followed by a slower nonradiative relaxation of the triplet state on the nanosecond time scale. Furthermore, the values of 3s and 3px Rydberg states of 2,4-difluoroanisole were experimentally determined to be 5.02 and 6.28 eV.