Nanosecond laser pulse photolysis was used to investigate the excited-state dynamics of the photonuclease vitamin-K3 (VK3). A spectral band peaked at 285 nm was newly observed and attributed to the triplet-excited sta...Nanosecond laser pulse photolysis was used to investigate the excited-state dynamics of the photonuclease vitamin-K3 (VK3). A spectral band peaked at 285 nm was newly observed and attributed to the triplet-excited state of VK3. In studying the photochemistry between the photonu-clease VK3 and guanine nucleotide (dGMP), we obtained spectroscopic evidence for the photo-initiated formation of both VK3 radical anion and dGMP radical cation, and thus proved the charge transfer reaction between the trip-let-excited VK3 and the ground-state dGMP.展开更多
UV-Vis, fluorescence spectroscopy and time resolved spectroscopic technique on picosecond and femto- second scales have been utilized to investigate the effect of steric hindrance and multiple hydroxyl groups of solve...UV-Vis, fluorescence spectroscopy and time resolved spectroscopic technique on picosecond and femto- second scales have been utilized to investigate the effect of steric hindrance and multiple hydroxyl groups of solvents on the barrierless isomerization in excited state of 3, 3′- di(3-sulfopropyl)thiacyanine triethylaminium salt. The re-sults show that the factors mentioned above may be respon-sible for a different 搒hort-time behavior?of the bleaching signal on the ground state and nonlinear viscosity depend-ence of the excited-state lifetime in isopropanol and glycol. These phenomena are distinguished from the situation re-ported in the long-chained monohydroxyl alcohol solvents. However, the dye molecule still exhibits the analyzing- wavelength dependence of the observed fluorescence lifetime, that is, the fluorescence lifetime increases with the increasing of analyzing-wavelength. The conclusions are in agreement with those drawn from femtosecond upconversion fluores-cence experiments and further exemplify the barrierless isomerization model in the excited state.展开更多
文摘Nanosecond laser pulse photolysis was used to investigate the excited-state dynamics of the photonuclease vitamin-K3 (VK3). A spectral band peaked at 285 nm was newly observed and attributed to the triplet-excited state of VK3. In studying the photochemistry between the photonu-clease VK3 and guanine nucleotide (dGMP), we obtained spectroscopic evidence for the photo-initiated formation of both VK3 radical anion and dGMP radical cation, and thus proved the charge transfer reaction between the trip-let-excited VK3 and the ground-state dGMP.
基金supported by the State Key Basis Research and Development Plans(Grant No.G1998010100)the National Natural Science Foundation of China(Grant Nos.3989039 and 90101010).
文摘UV-Vis, fluorescence spectroscopy and time resolved spectroscopic technique on picosecond and femto- second scales have been utilized to investigate the effect of steric hindrance and multiple hydroxyl groups of solvents on the barrierless isomerization in excited state of 3, 3′- di(3-sulfopropyl)thiacyanine triethylaminium salt. The re-sults show that the factors mentioned above may be respon-sible for a different 搒hort-time behavior?of the bleaching signal on the ground state and nonlinear viscosity depend-ence of the excited-state lifetime in isopropanol and glycol. These phenomena are distinguished from the situation re-ported in the long-chained monohydroxyl alcohol solvents. However, the dye molecule still exhibits the analyzing- wavelength dependence of the observed fluorescence lifetime, that is, the fluorescence lifetime increases with the increasing of analyzing-wavelength. The conclusions are in agreement with those drawn from femtosecond upconversion fluores-cence experiments and further exemplify the barrierless isomerization model in the excited state.
