Qual è la più piccola goccia d'acqua?

This presentation will bring the reader on a journey across the microscopic world of water clusters. After a brief introduction about molecular spectroscopy, I will show how the semiclassical approximation to quantum molecular dynamics allows for accurate full-dimensional quantum simulations of water cluster vibrational spectra, differently from classical molecular dynamics approaches. I will employ the semiclassical spectroscopy tool to determine the minimal network of surrounding water molecules needed to make the central one display the same vibrational features of liquid water. Remarkably, the minimal surrounding structure eventually responsible for proper solvation is made of just a few water molecules and includes two complete solvation shells.