1. Dipartimento di Matematica e Fisica and Interdisciplinary Laboratories for Advanced Materials Physics, Università Cattolica del Sacro Cuore, via Musei 41, I-25121 Brescia, Italy
2. BeDimensional SpA, via Albisola 121, 16163 Genova, Italy
3. Department of Theoretical Chemistry, Vrije Universiteit Amsterdam, De Boelelaan 1083, 1081HV Amsterdam, The Netherlands