Spectroscopy and Computational Chemistry Group - SC2
Computational Photochemistry, Photophysics and Spectroscopy of Photoresponsive Molecular Materials
Development and application of computational tools for modelling accurate photoinduced dynamics of complex photoresponsive molecular systems in realistic conditions, including their underlying multi-pulse transient spectroscopies at various spectral regimes, spanning the NIR-VIS-UV-Xray spectral window. The aim is not only to obtain a reproduction/interpretation of experimental data, but to build predictive models and provide a deeper understanding of the phenomena that are investigated. Eventually, the characterization and analysis of photoactive molecular materials (from simple isolated molecules to biological photoreceptors and complex molecular architectures including environment effects) is employed for the design of novel and smart materials (e.g., photochromic systems, molecular switches, etc) with tailored properties, encompassing a tunable photophysics and a controlled (photo)reactivity. This is achieved by using a worldwide unique set of tools in Computational (Photo)Chemistry and Spectroscopy that is developed by the group.
This research line is devoted to the prediction of structural, electronic and chemical properties of functional materials, including organic soft matter, biological systems and catalysts, through computer simulations (Molecular Dynamics, Metropolis and Kinetic Monte Carlo) methods, quantum chemistry calculations and network analysis. Particular attention is devoted to the comparison with experiments and the quantitative accuracy of the results, achieved by: i) careful modeling and testing of classical intermolecular potentials at various levels of resolution ii) adequate statistics provided by large system sizes and long simulations; iii) development of software tools for the calculation of observables directly or indirectly measurable with experimental techniques; iv) simulating thermodynamic equilibrium and non-equilibrium processes in realistic conditions. This array of techniques is applied to the molecular design of advanced materials possessing liquid crystalline, organic semiconducting, catalytic and light emitting properties and to characterization of complex phenomena, like chemical signaling in proteins.
The group’s interests focus on the experimental and computational study of structural and spectroscopic properties of organic molecular crystals, but include also liquids and glasses. These systems are characterized by interactions between large numbers of atomic or molecular components, which lead to qualitatively new cooperative behaviour at the macroscopic scales.
The group is also focused in high resolution molecular spectroscopy. The study of vibro-rotational spectra, especially if conducted on different isotopologists of the same molecule, provides the energies and spectroscopic constants of the analyzed levels. Furthermore, the analysis of excited vibrational states that have Fermi or Coriolis resonances allows the determination of the interaction parameters, related to the molecular dynamics related to energy transfers. Often, the infrared analysis of these molecules is complemented by a Raman study and theoretical calculations. The main system of interest are molecules of atmospheric, astrophysical or theoretical interest due to their model structure.
Experimental techniques such as micro-Raman, micro-IR, high resolution IR (up to 0.004 cm-1), UV/visible spectroscopic methods, together with X-ray and AFM measurements in collaborations with other researchers, allow for the investigation of the crystalline solids both in bulk and thin-film phases. A posteriori dispersion corrected DFT simulations and ab-initio molecular dynamics are employed to understand the spectroscopic properties and elucidate processes such as phase transitions and structural transformations in these systems.
