Raman Spectra Of Water Research Articles

Pressure Determination by Raman Spectra of Water in Hydrothermal Diamond-Anvil Cell Experiments

Pressure Determination by Raman Spectra of Water in Hydrothermal Diamond-Anvil Cell Experiments

Unified description of temperature-dependent hydrogen-bond rearrangements in liquid water

The unique chemical and physical properties of liquid water are a direct result of its highly directional hydrogen-bond (HB) network structure and associated dynamics. However, despite intense experimental and theoretical scrutiny spanning more than four decades, a coherent description of this HB network remains elusive. The essential question of whether continuum or multicomponent ("intact," "broken bond," etc.) models best describe the HB interactions in liquid water has engendered particularly intense discussion. Most notably, the temperature dependence of water's Raman spectrum has long been considered to be among the strongest evidence for a multicomponent distribution. Using a combined experimental and theoretical approach, we show here that many of the features of the Raman spectrum that are considered to be hallmarks of a multistate system, including the asymmetric band profile, the isosbestic (temperature invariant) point, and van't Hoff behavior, actually result from a continuous distribution. Furthermore, the excellent agreement between our newly remeasured Raman spectra and our model system further supports the locally tetrahedral description of liquid water, which has recently been called into question.

Studies on the Effects of Inorganic Ions and their Concentrations on Raman Spectra of Water

Studies on the Effects of Inorganic Ions and their Concentrations on Raman Spectra of Water

Raman-Spectra of Water in Crystalline Hydrates

Abstract Water s-retching bands of crystalline hydrates demonstrate a relative small effect of ions on water spectra. Water band shifts are mainly not bigger than in ice with some exceptions. The reasons of this observation are discussed.

Low-frequency (30--400 cm^-1) Raman Spectra of Water in Cellulose Gels.

Low-frequency (30--400 cm^-1) Raman Spectra of Water in Cellulose Gels.

Raman Spectra of Water in Concentrated Ionic Solutions

Photoelectric Raman spectra of solutions of the four potassium halides and of Be2+, Mg2+, Cu2+, Zn2+, Sn2+, Al3+, La3+, and Pr3+ chlorides in ordinary water and in 5 mole % deuterated water show, in the region of the water stretching fundamentals, single broad bands similar to those of the pure solvents. Peak frequency shifts between solutions are small, about 1% or of the order of the available resolution, and are insensitive to the cation, except in the ZnCl2 solutions. Intensity and bandwidth changes are large, in the range 20%−100%, but these also correlate with the halide ion in the order F−<H2O<Cl−<Br−<I−. Direct cation effects are absent, even in solutions containing colored Cu2+ and Pr3+ ions near resonance with the 4358-Å exciting light, but in all of the solutions containing polyvalent cations, the molar intensity effect of Cl− is less than it is in KCl. The observed intensities can be related to anion effects when the Raman intensity behavior in solution is interpreted in terms of contribution by both components to the intermediate state of the scattering process, if complex formation is a common occurrence between chloride and polyvalent cations. Despite the strong excited-state interaction underlying intensity behavior, there is no indication that ion—water association leads to the large changes in frequencies or bandwidths of the water stretching fundamentals which are implied by a rigid hydration model of the ion in solution.

The Raman Spectra of Water, Aqueous Solutions and Ice

The Raman spectra of water at different temperatures, of aqueous solutions and of ice have been discussed in detail. Several low frequency shifts such as Δν̃ 150, 445 and the shift at 2170 are easily discernible if ultraviolet excitation is used. The first two of these vary markedly in intensity with temperature changes and are affected by some solutes. All three are present in ice at slightly displaced frequencies. At least some of these frequencies may be ascribed to the intermolecular influences. Whatever may be the mechanism of polymerization or association these results indicate that effectively such a state exists and is a function of environmental conditions.