Surface Stress And Raman Spectrometrics Of Alkali Halide Solutions

Salt ions affect not only the stability and solubility of proteins and other macromolecular solution, but also the surface tension, viscosity and phrase transition of water. To clarify the mechanism of interactions between ions and proteins or water is of great importance in chemistry, biology, environment and other area. Hofmeister effect remains mysterious despite intensive investigations. Known theoretical models can only explain few certain properties of Hofmeister serials. Therefore, introducing new thought to explore the mechanism between ions and water is a challenging and meaningful work.A combination of hydrogen bond cooperative relaxation model and differential Raman phonon spectrometrics and contact angle measurements, this thesis strive to clarify and quantify hydrogen bond(HB or O:H-O) relaxation and molecular dynamics behavior in the hydration shell of YX(X = F, Cl, Br, I; Y = Na, K, Rb, Cs) type alkali halide. Firstly, we constructed a model of ions electric field induced hydrogen bond cooperative relaxation, then measured the Raman spectra and contact angle of different samples, we also created a novel method, differential phonon spectrometric. The following summarizes the progresses:1. The aqueous ions create each an point electric field or dipole electric field that aligns, clusters, polarizes water molecular dipoles to form the hydration shells through electrostatic interaction.2. The ionic polarization shares the same effect of molecular undercoordination and heating that shortens the H-O bond and stiffen its phonon, and meanwhile, the O-O Coulomb repulsion lengthen and soften the O:H nonbond with an association of polarization.3. Salt ions electric fields induce phonon frequency shifts and contact angle change which are very sensitive to concentration, salt type, coordination environment. compared to cations, anions display more obvious. Relative changes associate with ionic radii and electronegative characteristics, and follows the Hofmeister serials, for anion, X-(R/?) = I-(2.2/2.5) > Br-(1.96/2.8) > Cl-(1.81/3.0) > F-(1.33/4.0) ? 0, and cation, Y+(R/?) = Na+(0.98/0.9) > K+(1.33/0.8) > Rb+(1.49/0.8) > Cs+(1.65/0.8).4. O:H-O electrification raises the molecular structure order, skin stress, solution viscosity and thermal stability.The consistency of theory and experiment not only deepens our insight into the salt solute-solvent interaction involved in the Hofmeister Series in terms of O:H-O bond electrification but also provides a powerful means quantifying the dynamic, local, molecular-site-resolved information regarding the O:H-O bond cooperatively in aqueous solutions.