Femtosecond time-resolved absorption spectroscopy was employed to investigate the relaxation dynamics of photoexcited copper(II) tetrakis (4-N-methylpyridyl)porphyrin (Cu(II)(TMpy-P4)) in neat water. The transient absorption spectra and their temporal profiles show a strong pump-power dependence reflecting multiphoton ionization of water, which probably caused the discrepancies in the previous reports. Time-resolved transient absorption spectra were recorded under low pump-power condition to avoid the multiphoton effect. It was confirmed that the relaxation process finishes within 100 ps, exhibiting the double exponential recovery of Cu(II)(TMpy-P4) ground state. The relevant mechanism for the relaxation dynamics of photoexcited Cu(II)(TMpy-P4) in water was proposed.
Bibliographical noteFunding Information:
This work was financially supported by Korea-Japan Exchange Program of Ministry of Education of Japan.
All Science Journal Classification (ASJC) codes
- Physics and Astronomy(all)
- Physical and Theoretical Chemistry