Relevance of pi sigma* states in the photoinduced processes of adenine, adenine dimer, and adenine-water complexes.
Ab initio calculations and time-resolved photoionization spectroscopy were carried out to characterize the role of the lowest two pi sigma* excited states for the photoinduced processes in the adenine monomer, adenine dimer, and adenine-water clusters. The calculations show--with respect to the monomer--a stabilization of 0.11-0.14 eV for the pi sigma* states in different isomers of adenine dimer and an even bigger stabilization of 0.14-0.36 eV for isomers of adenine-(H2O)1 and adenine-(H2O)3. Hence, the stabilized pi sigma* states should play an important role in the excited-state relaxation of partially or fully solvated adenine. This conclusion is supported by experimental results: In the adenine monomer, strong n pi* state signals are observed. Those signals are reduced in adenine dimer and vanish in water clusters due to the competing relaxation via the pi sigma* states.
Ritze
H-H
HH
Max Born Institute, Max-Born-Strasse 2A, D-12489, Berlin-Adlershof, Germany. ritze@mbi-berlin.de
Lippert
H
H
Samoylova
E
E
Smith
V R
VR
Hertel
I V
IV
Radloff
W
W
Schultz
T
T