Andrzej L. Sobolewski

TL;DR: In this article, the authors combined results of ab initio electronic-structure calculations and spectroscopic investigations of jet-cooled molecules and clusters provide strong evidence of a surprisingly simple and general mechanistic picture of the nonradiative decay of biomolecules such as nucleic bases and aromatic amino acids.

TL;DR: Experimental and theoretical evidence is presented for an excited-state deactivation mechanism specific to hydrogen-bonded aromatic dimers, which may account, in part, for the photostability of the Watson-Crick base pairs in DNA.

TL;DR: It is suggested that internal-conversion processes via conical intersections, which are accessed by out-of-plane deformation of the six-membered ring, dominate the photophysics of the lowest vibronic levels of adenine in the gas phase, while hydrogen-abstraction photochemistry driven by repulsive (1)pisigma states may become competitive at higher excitation energies.

TL;DR: The computational results support the conjecture that the photochemistry of hydrogen bonds plays a decisive role for the photostability of the molecular encoding of the genetic information in isolated DNA base pairs.

TL;DR: In this paper, the authors investigated the low-lying excited singlet states of the guanine-cytosine base pair with multi-reference ab initio methods (complete-active-space self-consistent field (CASSCF) method and second-order perturbation theory based on the CASPT2).