Self-Modeling Curve Resolution Study of Temperature-Dependent Near-Infrared Spectra of Water and the Investigation of Water Structure

A self-modeling curve resolution method called Simplisma is used to investigate the 1300−1600 nm near-infrared region of the water spectrum. The most specific wavelengths of the analytes present are identified through the ratios of the standard deviations to the means of spectroscopic variations for all of the wavelengths. Without any prior knowledge about the system or supplementary experimental data, we demonstrate that only two species are enough to represent more than 99% of the original data with at least one additional spectroscopically identifiable component. The features of the species and their concentration profiles are calculated. The results are discussed in light of several previous spectroscopic and theoretical studies of water. It is found that a quasi-lattice model with broken hydrogen bonds is highly supported by the present study.