Its exceptional properties have puzzled scientists for generations, and many fundamental questions concerning the properties of water are still unresolved (see, e.g., Refs. 2-5 and references therein). Many chemical and most biological processes crucially depend on water as a solvent , and solvent effects intricately determine both the structure and spectroscopic properties of solvated molecular systems. In turn, solutes change the structure and properties of liquid water by influencing water-water interactions .