Forward-headed structure change of acetic acid–water binary system by stimulated Raman scattering

The acetic acid-water binary system is a classical hydroxy-carboxy mixed system, while new and interesting phenomena appear under stimulated Raman scattering(SRS).Compared with the weaker signal of the acetic acid-water binary system obtained in spontaneous Raman scattering, SRS provides a finer band and a relatively distinct structural transition point.The structural transformation points are respectively at 30% and 80% by volume ratio under the condition of spontaneous Raman spectroscopy, while they are respectively at 15% and 25% under the condition of SRS.This phenomenon is attributed to the generation of laser induced plasma and shockwave induced dynamic high pressure environment during SRS.

Raman investigation of hydration structure of iodide and iodate

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(IO_(3)^(-)) in the seawater.Therefore,understanding the interactions between I^(-),IO_(3)^(-)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^(-),IO_(3)^(-)and water molecules quickly and accurately.Herein,the effect of I^(-)and IO_(3)^(-)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 IO_(3)^(-),which indicates that I^(-)is more likely to form the hydration structure with water than IO_(3)^(-).These results contribute to analyzing the different interactions between I^(-)-water and IO_(3)^(-)-water,then helping to prevent ozone depletion.