Lifetime of low-density water domains in salt solutions by time-resolved Delayed Luminescence

Liquid water is described in two-state theory as mixture of localised molecular arrangements having different structure and density, the low-density (LDW) and high-density water (HDW). Theoretical calculations describe the formation of LDW and/or HDW domains, while their lifetime remains unknown. As ions partition selectively into LDW or HDW, modifying the water structuring, time-resolved photo-induced Delayed Luminescence (DL) of different salts solutions was measured. When formation of LDW domains is foreseen, significant DL signal was found, whose decay-time probability distribution is maximum in microsecond range. This result suggests the existence of such long lifetimes structures, which can participate in biological processes.