Formation of Long-Lived Dark States during Electronic Relaxation of Pyrimidine Nucleobases Studied Using Extreme Ultraviolet Time-Resolved Photoelectron Spectroscopy

Autor: Yuta Miura, Yo-ichi Yamamoto, Shutaro Karashima, Natsumi Orimo, Ayano Hara, Kanae Fukuoka, Tatsuya Ishiyama, Toshinori Suzuki
Rok vydání: 2023
Předmět:
Zdroj: Journal of the American Chemical Society. 145:3369-3381
ISSN: 1520-5126
0002-7863
Popis: Ultrafast electronic relaxation of nucleobases from ¹ππ* states to the ground state (S0) is considered essential for the photostability of DNA. However, transient absorption spectroscopy (TAS) has indicated that some nucleobases in aqueous solutions create long-lived ¹nπ*/³ππ* dark states from the ¹ππ* states with a high quantum yield of 0.4–0.5. We investigated electronic relaxation in pyrimidine nucleobases in both aqueous solutions and the gas phase using extreme ultraviolet (EUV) time-resolved photoelectron spectroscopy. Femtosecond EUV probe pulses cause ionization from all electronic states involved in the relaxation process, providing a clear overview of the electronic dynamics. The ¹nπ* quantum yields for aqueous cytidine and uracil (Ura) derivatives were found to be considerably lower (
Databáze: OpenAIRE