Mio Matsui

Abstract The near-infrared spectra of ultrapure water and five types of ionic aqueous solutions were recorded under normal and simulated microgravity (< 0.1 G). The water band at approximately 1450 nm, corresponding to the combination of O–H symmetric and antisymmetric stretching vibrations, was analyzed. The results showed that the hydrogen-bond network (HBN) weakened in both ultrapure water and all ionic solutions under microgravity.