TIME DEPENDENT DENSITY FUNCTIONAL THEORY ... - TDDFT.org

Ultrafast dissociation of adenine-water
hydrogen bonds by photoexcitation.
Myrta Grüning ⋆ , Alberto Castro • , Angel Rubio ⋆,‡
⋆ Donostia International Physics Center;
• Departamento de Física Teórica, Universidad de Valladolid;
‡ Departamento de Física de Materiales, Facultad de Químicas, Universidad del País Vasco
Recent molecular-beam studies of hydrated cluster of adenines show the anomalous loss of the
solvent molecules after excitation by a nanosecond laser pulse at 262 nm[1,2].
The goal of this work is to provide the molecular mechanism behind this phenomenon working
within the time-dependent density functional theory (DFT) framework.
The dissociation of the hydrogen bonds has been attributed to the dissociative character of
the potential energy surface in the excited state: we investigate this hypothesys calculating the
evolution of the system after the interaction with the laser pulse with real-space real-time time
dependent DFT.
Preliminary ground state and linear response time dependent DFT calculations indicate that
the potential energy surface in the excited state is not dissociative, but the excitation provides the
complex with enough energy to dissociate.
[1] Kim et al. J. Phys. Chem. A (2000) 104, 6552. [2] Kang et al. Chem. Phys. Lett.
(2002) 359, 213.
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