| | | | | | | webmail : intra-extra| Accès VPN| Accès IST| Contact
Cytosine excited state dynamics studied by femtosecond absorption and fluorescence spectroscopy
A. Sharonov, T. Gustavsson, V. Carré, E. Renault, D. Markovitsi, Chem. Phys. Lett., 2003, 380, 173.
logo_tutelle logo_tutelle 
Cytosine excited state dynamics studied by femtosecond absorption and fluorescence spectroscopy

The fluorescence anisotropy (upper panel) and the total fluorescence (lower panel) decays determined for a 2 × 10−3 M aqueous solution of cytosine at 330 nm after excitation at 267 nm

We report a femtosecond spectroscopic study of the DNA base cytosine in aqueous solution at room temperature. Two different experimental techniques were used, fluorescence upconversion and transient absorption, providing complementary information on the excited state relaxation. While the fluorescence decay is clearly bi-exponential, with an ultrafast (0.2 ps) and a slower (1.3 ps) component, the decay of the transient absorption signal is mono-exponential with a 1.1 ps characteristic time. In addition, the fluorescence anisotropy is also found to decay in a bi-exponential manner. The results are discussed in terms of possible non-radiative relaxation processes that may intervene in the deactivation of the excited state.

 
#1180 - Last update : 01/20 2009

 

Retour en haut