1. Department of Physics
and Earth Sciences, University of Ferrara, via G. Saragat 1, 44122, Ferrara, Italy
2. Eni Spa, San Donato Milanese Research Center, via F. Maritano 26, 20097, San Donato Milanese, Italy
3. Eni Spa, Renewable
Energy and Environmental Laboratories, via G. Fauser 4, 28100 Novara, Italy