Research

 

My main research line focuses on theoretical study of the photophysics, photochemistry, natural dynamics and, when relevant, the design of strategies to exert control on systems of biological or chemical interest. The understanding of the mechanisms behind photoinduced reactions has considerably evolved thanks to the recognition that potential energy surfaces corresponding to different excited states may become degenerate. These degeneracy regions, which allow for a very efficient non adiabatic energy/population transfer between sates of the same (conical intersections, CI) or different spin multiplicity (intersystem crossings, ISC), serve as very fast non radiative funnels for accessing lower electronic states. Far from rare, CI and ISC are ubiquitous in photochemistry and photophysics and have been key for understanding important phenomena such as photosynthesis, vision or the stability of the genetic code.

Particularly interesting are photoinduced processes connected to singlet oxygen (1O2) generation. The extreme reactivity of 1O2, which mediates the oxidative degradation of many organic molecules, confers this diradical a key role in photoaging and photocarcinogenesis, but has also been exploited in photodynamic chemotherapy of cancer or the photoinactivation of viruses and bacteriae. Although seminal work has been done on 1O2 production from the singlet manifold of endoperoxide photosensitizers, (see applicant’s CV), very little is known on the mechanism that triggers 1O2 generation from the triplet excited state T1 of the photosensitizers (PSs). Understanding the mechanism by which T1 state is populated and its competition with the decay to the ground state through internal conversion is crucial for designing new strategies for inhibiting/promoting ISC processes. The clinical PSs based on the porphyrazine molecule or Ru (II) complexes and the endogenous skin PS N-formylkynurenine are just some interesting examples which might be worth studying.

Throughout my research career I have tackled the following research lines under the perspective of my formation as quantum chemist.

  • Reactions occurring in the atmosphere and astrochemical processes.
  • Bonding and reactivity of ion-molecule complexes.
  • Excited state proton transfer reactions.
  • Competitive photochemical reactions.
  • Photoinduced electron transfer processes and new photovoltaic materials.
  • Self-assembled organic acids and alcohols on Au (111) surfaces.