An ab-initio approach to describe coherent and non-coherent exciton dynamics Davide Sangalli, Enrico Perfetto, Gianluca Stefanucci and Andrea Marini Eur. Phys. J. B, 91 8 (2018) 171 Published online: 01 August 2018 DOI: 10.1140/epjb/e2018-90126-5