Electronic structure of adenine and thymine base pairs studied by femtosecond electron-ion coincidence spectroscopy.
Femtosecond pump-probe spectroscopy was combined with photoelectron-photoion coincidence detection to investigate the electronic structure and dynamics of isolated adenine (A) and thymine (T) dimers and the adenine-thymine (AT) base pair. The photoelectron spectra show that pipi* and npi* states are only weakly perturbed in the hydrogen-bound dimers as compared to the monomers. For cationic base pairs with internal energies greater than 1 eV, we observed considerable cluster fragmentation into protonated monomers. This process selectively removed signals from the npi* --> n-1 ionization channel in all dimers. The photoelectron spectra are compared to time-resolved mass spectra and confirm the assignment of short-lived pipi* and npi* populations in the adenine, thymine, and mixed AT dimers.
Gador
Niklas
N
Steacie Institute for Molecular Sciences, National Research Council, 100 Sussex Drive, Ottawa, K1A 0R6 Canada.
Samoylova
Elena
E
Smith
Valoris Reid
VR
Stolow
Albert
A
Rayner
David M
DM
Radloff
Wolfgang
W
Hertel
Ingolf Volker
IV
Schultz
Thomas
T
D000225:Adenine / Q000737:chemistry*; D020029:Base Pairing; D019281:Dimerization; D004583:Electrons; D006860:Hydrogen Bonding; D008027:Light; D013058:Mass Spectrometry / Q000379:methods*; D015394:Molecular Structure; D013941:Thymine / Q000737:chemistry*
D000225:Adenine; D013941:Thymine