1. Materials Chemistry Research Group, Lash Miller Chemical Laboratories, Department of Chemistry, University of Toronto, Toronto, Ontario, M5S 3H6 Canada, and European Laboratory for Non-Linear Spectroscopy (LENS) and INFM-MATIS, University of Florence, Polo Scientifico, Via Nello Carrara 1, I-50019, Sesto Fiorentino, Firenze, Italy