In collaboration with the group of Prof. V. Barone at the Scuola Normale Superiore of Pisa (http://dreamslab.sns.it/ ) we are developing new integrated multilevel computational approaches for studying spectroscopic observables of complex biological and inorganic systems. Within the plethora of modern experimental techniques, vibrational, electronic, and resonance spectroscopies are uniquely suitable to probe static and dynamic properties of molecular systems under realistic environmental conditions and in a non-invasive fashion. Indeed, the impact of spectroscopic techniques in practical applications is huge, ranging from astrophysics to drug-design and biomedical studies, from the field of cultural heritage to characterizations of materials and processes of technological interest, etc. However, the development of more and more sophisticated experimental techniques poses correspondingly stringent requirements on the quality of the models employed to interpret spectroscopic results, and on the accuracy of the underlying chemical-physical descriptions. As a matter of fact, spectra do not provide direct access to molecular structure and dynamics, and interpretation of the indirect information that can be inferred from analysis of the experimental data is seldom straightforward. Typically these complications arise from the fact that spectroscopic properties depend on the subtle interplay of several different effects, whose specific roles are not easy to separate and evaluate.
In such a complex scenario, theoretical studies can be extremely helpful, essentially at three different levels: (i) supporting and complementing the experimental results to determine structural, electronic and dynamical features of target molecule(s) starting from spectral properties; (ii) dissecting and quantifying the role of different effects in determining the spectroscopic properties of a given molecular / supramolecular system; (iii) predicting electronic, molecular and spectroscopic properties for novel/modified systems. For this reason, computational spectroscopy is rapidly evolving from a highly specialized research field into a versatile and fundamental tool for the assignment of experimental spectra and their interpretation in terms of basic physical-chemical processes.