Our research group has a long and wide experience in the application of Theoretical Chemistry to the study of phenomena (structural, spectroscopic, kinetic and dynamic) of different areas of chemistry that can only be explained going beyond the study of the electronic movement. So, assuming that the Born-Oppenheimer approximation holds (when possible) in its entire extent, we have first determined the electronic structure (solving the electronic Schrödinger equation) of the systems being studied, and then we have treated the dynamics of the nuclei (contained in the nuclear Schrödinger equation). In the last years, the advance in theoretical methods and the increase in computer power have begun to make possible that biological macromolecules can be treated by the same methods that were exclusively restricted in the past to small chemical molecules. In fact, biological molecules are governed by the same physical laws than chemical molecules, although the bigger dimensions of the former introduce additional difficulties and cooperative phenomena.

During the last years we have been using different dynamical approximations to analyze some problems of Chemistry and we have taken advantage of that experience to extend now that methodology (conveniently modified) to problems of Molecular Biology, being always problems that need of an accurate treatment of nuclear dynamics. The particular dynamical methodology selected to simulate the reactivity of a particular system depends on the characteristics of that problem: we have used from Molecular Classical Dynamics to Quantum Dynamics, and also considering statistical approaches to nuclear dynamics as Variational Transition State Theory in all its different forms. Obviously, in all those cases the electronic problem must be solved first, and due to the electronic characteristics of the systems we have studied, this first part has been many times a challenge in itself. In the study of nuclear dynamics there are not so many standard methods as in the study of molecular electronic structure. For this reason a part of our research has consisted in the development of methodology for the nuclear dynamical study of reacting systems, and in the development of new codes (or the improvement of existing packages) adapted to each chemical or biochemical problem.

Our research group at the Chemistry Department of the UAB originated in the field of Chemistry has shifted its interest increasingly towards the theoretical study of biological systems (mainly enzymatic reactions and photobiological processes so far) taking advantage precisely of its experience with the dynamical methods of use in chemical reactivity. The extension of our research field to biological problems has caused that part of our group is also member of the Institute of Biotechnology and Biomedicine of the Universitat Autònoma de Barcelona since 2002.

As a consequence of that thematic evolution to the field of what could be named as Theoretical Molecular Biology, some of the traditional chemical research lines of our group have been relegated for the moment. Two of them merit special mention:

  1. Quantum effects in chemical systems involving light atoms.
  2. The first studies in our group on quantum effects (for instance, hydrogen/proton transfers) in systems with light atoms date back to 1989 when Prof. Miquel Moreno came back from his pot-doctoral stay at the University of California (Berkeley) under the supervision of Prof. W.H. Miller and was finally consolidated when Dr. Ricard Gelabert also came back from his nearly 2 years and a half post-doctoral stay in the group of Prof. Miller. Initially the study of hydrogen/proton transfers was limited to the ground electronic state but later hydrogen/proton transfers in electronic excited states were also considered. It is worth mentioning that in a series of polyhidride/dihydrogen complexes of transition metals we were able to explain several dynamic effects like the rotational tunnelling in dihydrogen complexes; the quantum exchange coupling in polyhidrides (with coupling constants bigger than 1000 Hz); the temperature dependence of H-D spin-spin coupling constants; the hydrogen elimination from several excited electronic states; and the existence and properties of elongated dihydrogen complexes and compressed dihydride complexes.

  3. Atmospheric Chemistry.
  4. The calculation of rate constants for reactions of Atmospheric Chemistry has been developed in our group since 1991 when Prof. Àngels González-Lafont joined again our group in our university after her post-doctoral research stay at the University of Minnesota under the supervision of Prof. D.G. Truhlar (one of the fathers of Variational Transition State Theory). Afterwards other members of the group have also visited Minnesota and different scientific collaborations with Prof. Truhlar and other groups working on the same topic have been established along the years. We studied the kinetics and mechanism of a wide variety of reactions involving many radicals and many different organic molecules. We analyzed and interpreted several kinetic experimental data corresponding to those reactions: negative activation energies, kinetic isotope effects, tunnelling corrections to the rate constant values, etc.


6 / 3 / 2012

The new web of the dynamics group has been released.