“Ab initio” simulation of the excitonic properties of light-harvesting complexes

Benedetta Mennucci
Department of Chemistry, University of Pisa, via G. Moruzzi 13, Pisa, Italy

In Nature, electronic interactions among different chromophoric units are used to tune the optical properties of light-harvesting complexes and control the photo-induced processes at the basis of their biological function. As a result, the linear and nonlinear optical spectra of each complex become a unique fingerprint, which, in principle, can be used to obtain detailed information about its nuclear and electronic nature. Unfortunately, such an analysis is made difficult by two effects: (i) the coupling of the electronic processes with nuclear motions and (ii) the “disorder” introduced by the surrounding environment. The two effects play a fundamental role in determining the supramolecular excitonic states and the resulting spectroscopic signals. Here it will be shown that an “ab initio” strategy can be successfully used by combining molecular dynamics simulations with quantum chemical descriptions of the interacting chromophores within their natural environment.[1] Examples of light-harvesting pigment-protein complexes from different photosynthetic organisms will be presented and discussed.[2,3]

References

[1] C. Curutchet, B. Mennucci, Chem. Rev. 2016, DOI: 10.1021/acs.chemrev.5b00700.
[2] S. Jurinovich, L. Viani, L., I. G. Prandi, T. Renger, B. Mennucci, Phys Chem Chem Phys. 2015, 17, 14405.
[3] L. Cupellini, S. Jurinovich, M. Campetella, S. Caprasecca, C. A. Guido, S. M. Kelly, A. T. Gardiner, R. Cogdell and B. Mennucci, 2016, submitted.