Hyper‐Raman study of hydrated excess protons in water: Measurement of concentrated HCl solution. (25th March 2022)

• Record Type: Journal Article
• Authors: Inoue, Kazuki; Okuno, Masanari
• Other Names: Yamaguchi Shoichi guestEditor.; Tsenkova Roumiana guestEditor.; Hamaguchi Hiro‐o guestEditor.
• Is Part Of: Journal of Raman spectroscopy. Volume 53:Number 10(2022)
• Page Start: 1679
• Page End: 1685
• Publication Date: 2022-03-25
• Subjects: electrolyte -- excess proton -- hyper‐Raman spectroscopy -- proton continuum -- water; Raman spectroscopy -- Periodicals; 535.846
• DOI: 10.1002/jrs.6342
• Languages: English
• ISSNs: 0377-0486

Abstract

Abstract: We report hyper‐Raman (HR) spectra of concentrated hydrochloric acid solutions for the first time. HR signals from the OH stretching region to the low‐frequency region reflect the presence of chloride anions solvated in water. By contrast, it turns out that HR spectroscopy is insensitive to the presence of excess protons in water. HR spectra of HCl solutions do not show any signature of a proton continuum and shoulders on the high/low‐frequency sides of the bending mode of H2 O in stark contrast to IR spectroscopy. Moreover, we found that a sharp HR signal around 500 cm −1 appear in 532 nm excited HR spectra. A laser power dependence indicates that this signal comes from a photochemical reaction. The absence of this signal under 1064 nm HR excitation and 532 nm Raman excitation suggests that the resonance (hyper‐)Raman effect enhances the signal from the photoproduct. Abstract :