1. Electronic structure of adenine and thymine base pairs studied by femtosecond electron-ion coincidence spectroscopy.
- Author
-
Gador N, Samoylova E, Smith VR, Stolow A, Rayner DM, Radloff W, Hertel IV, and Schultz T
- Subjects
- Base Pairing, Dimerization, Hydrogen Bonding, Molecular Structure, Adenine chemistry, Electrons, Light, Mass Spectrometry methods, Thymine chemistry
- Abstract
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.
- Published
- 2007
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