Beyond classical theories

Both Classical Nucleation Theory (CNT) and ground state adiabatic descriptions of matter have taught us a great deal about nucleation phenomena. However, recent experiments have confirmed the existence of luminescence, in both the deep UV and visible regions, during crystallization of NaCl from solution - referred to as crystalloluminescence (XTL). Given the difficulty in experimentally probing the underlying nucleation mechanisms in condensed phases, the emission of radiation is characteristic of the chemical processes giving rise to that emission. This opens the possibility of using XTL as an exquisite probe of nucleation mechanisms. The inclusion of electronically excited states in the nucleation mechanism lies beyond both CNT and ground state adiabatic interactions. Here we outline the chemical physics relevant to these findings and their consequences on how we understand and model nucleation.