title: Surprising Hofmeister Effects on the Bending Vibration of Water.
abstract: The Hofmeister series, which originally described the specific ion effects on the solubility of macromolecules in aqueous solutions, has been a long-standing unsolved and exceptionally challenging mystery in chemistry. The complexity of specific ion effects has prevented a unified theory from emerging. Accumulating research has suggested that the interactions among ions, water and various solutes play roles. However, among these interactions, the binding between ions and solutes is receiving most of the attention, whereas the effects of ions on the hydrogen-bond structure in liquid water have been deemed to be negligible. In this study, attenuated-total-reflectance Fourier transform infrared spectroscopy is used to study the infrared spectra of salt solutions. The results show that the red- and blue-shifts of the water bending band are in excellent agreement with the characteristic Hofmeister series, which suggests that the ions' effects on water structure might be the key role in the Hofmeister phenomenon.
authors.affiliation: Department of Chemistry, Renmin University of China, Beijing, 100872, China.
authors.forename: Chuanyu
authors.initials: C
authors.lastname: Yan
authors.affiliation: College of Materials Science and Technology, Beijing Forestry University, Beijing, 100083, China.
authors.forename: Zhimin
authors.initials: Z
authors.lastname: Xue
authors.affiliation: Department of Chemistry, Renmin University of China, Beijing, 100872, China.
authors.forename: Wancheng
authors.initials: W
authors.lastname: Zhao
authors.affiliation: Department of Chemistry, Renmin University of China, Beijing, 100872, China.
authors.forename: Jinfang
authors.initials: J
authors.lastname: Wang
authors.affiliation: Department of Chemistry, Renmin University of China, Beijing, 100872, China. tcmu@chem.ruc.edu.cn.
authors.forename: Tiancheng
authors.initials: T
authors.lastname: Mu
keywords: Hofmeister series; bending modes; hydrogen bonds; infrared spectroscopy; water