Low-Frequency Isotropic Raman Spectra of Concentrated Aqueous KX (X: Cl, Br, NO3, and SCN) Solutions

Abstract

Abstract Polarized Raman spectra for concentrated aqueous KX solutions (X: Cl, Br, NO3, and SCN) were measured in the frequency range of 30 ≤−1 in order to find the totally symmetric stretching vibrational mode of hydrated K+. The observed polarized peak intensities of the intermolecular vibrational mode at−1 in the isotropic spectra for KCl and KBr solutions exhibit systematic increase with increasing solute content. Polarized components at−1 were observed in the isotropic spectra for 5 mol % KNO3 and 7 mol % KSCN solutions, respectively. The position of these polarized peaks were found to shift to lower frequency by 7–15 cm−1 in D2O solutions, which is consistent with the expected value of the H/D isotopic shift calculated for the totally symmetric vibrational mode of the hydrated K+, K+(H2O)6.≤ 1000 cm= 160–180 cm= 166 and 167 cm