Raman investigation of hydration structure of iodide and iodate* *Project supported by the National Natural Science Foundation of China (Grant Nos. 11374123 and 12004132) and Science and Technology Planning Project and Talent Project of Jilin Province, China (Grant Nos. 20170204076GX, 20180101006JC, 20180101238JC, 20190201260JC, 20200201179JC, 2019C0355-5, JJKH20200935KJ, and JJKH20200936KJ)

Abstract

In the troposphere, the destruction of ozone and the formation of new particles are closely related to the iodine content, which mainly comes from iodide (I−) and iodate () in the seawater. Therefore, understanding the interactions between I−, and water molecules plays a certain role in alleviating the destruction of the ozone layer. Raman spectroscopy is commonly used to obtain the information of the interaction between I−, and water molecules quickly and accurately. Herein, the effect of I− and on the change in Raman band characteristics of water is investigated to reflect the associated intermolecular interactions change. With the addition of the two ions, the Raman band corresponding to OH stretching vibration moves towards the high wavenumber, indicating the formation of hydration structure. The narrowing of the Raman band from OH stretching vibration under weak hydrogen bond agrees well with the hydrogen bond variation, while the abnormal broadening of the Raman band from OH stretching vibration under strong hydrogen bond indicates the formation of H-down structure. With the increase of ions concentration, the frequency shift of the Raman band from OH stretching vibration under both weak and strong hydrogen bonds becomes more apparent. Meanwhile, the frequency shift of I− is more obvious than that of , which indicates that I− is more likely to form the hydration structure with water than . These results contribute to analyzing the different interactions between I−–water and –water, then helping to prevent ozone depletion.