Characteristic wavenumber shifts of the stimulated Raman scattering from interfacial water molecules induced by laser‐induced plasma generation at air–water and water–silver interfaces

Abstract

Stimulated Raman scattering (SRS) from water molecules in the air-water and water-silver interfacial regions is measured when laser-induced plasma are generated at these interfaces. In both cases, characteristic lower wavenumber shifts of the OH stretching vibrational modes of the interfacial water molecules are observed. The mechanisms of the characteristic lower wavenumber shifts are considered from two viewpoints. One is the electrostatic interactions between the interfacial water molecules and the excess electrons induced by the plasma generation at the interfacial area. The other is the coupling of the SRS with Brillouin scattering induced by a shock wave generation by abrupt volume expansion due to the phase transition from liquid to plasma. Differences between the obtained SRS spectra and vibrational spectra previously measured by a sum-frequency generation technique are also discussed.

Editorial

“…These include: a study on polarization-sensitive CARS spectroscopy of free-base porphyrins; [1] a study on the ultrafast bimolecular radical reaction between S 1 p-terphenyl and carbon tetrachloride; [2] a time-resolved resonance Raman and density functional theory study of the deprotonation reaction of the triplet state of para-hydroxybenzophenone in mixed acetonitrile/water solutions; [3] an investigation of femtosecond Raman-induced Kerr effect spectroscopy; [4] a paper on ultrafast vibrational dynamics and solvation complexes of methyl acetate in methanol studied by sub-picosecond infrared spectroscopy; [5] an ultrafast dynamics and photochemistry study of π − π * excited trans-azobenzene; [6] a paper on ultrafast dynamics in Cu(I)bisdiimine complexes from resonance Raman intensities; [7] a three-state model for femtosecond broadband stimulated Raman scattering; [8] a picosecond time-resolved ultraviolet resonance Raman study on photoinduced electron transfer in glucose oxidase; [9] a study on molecular vibrational imaging of a human cell by multiplex coherent anti-Stokes Raman scattering microspectroscopy using a supercontinuum light source; [10] a paper on characteristic wavenumber shifts of the stimulated Raman scattering from interfacial water molecules induced by laser-induced plasma generation at air-water and water-silver interfaces; [11] a study on the identification of chemical species of fluorescein isothiocyanate isomer-I (FITC) monolayers on platinum by doubly resonant sum-frequency generation spectroscopy; [12] a work on coherent acoustic phonons in a thin gold film probed by femtosecond surface plasmon resonance; [13] a review of recent advances in linear and nonlinear Raman spectroscopy; [14] an investigation of the halide-ion-assisted increase of surfaceenhanced hyper-Raman scattering; [15] and finally a study on ultrafast Raman loss spectroscopy [16] . …”

Hydrated-electron resonance enhancement O–H stretching vibration of water hexamer at air–water interface

“…Two SRS peaks were observed near the air-water interface at around 3400 and 3000 cm −1 , with corresponding anti-Stokes at −3400 and −3000 cm −1 . The wavenumber of the former peak near the air-water interface was close to that observed inside the water, indicating that the peak was derived from the water molecules inside water [18]. The former peak demonstrated a low hydrogen bond order structure.…”

“…The maximum irradiance for a Gaussian laser beam with energy of up to 100 mJ at 532 nm could be estimated at approximately 511 × 10 W cm −2 under a focal point at a laser filament diameter of 100 to 200 μm; the diameter of the optical focus is around 50 μm and the pulse duration is 8 ns. The maximum irradiance was sufficient to generate plasma through multiphoton ionization, followed by avalanche ionization [18].…”

Recent advances in linear and non‐linear Raman spectroscopy. Part III

“…Hence, it is important to know the SRS threshold. Characteristic wavenumber shifts of SRS from interfacial water molecules induced by laser-induced plasma generation at air-water and water-silver interfaces have been studied by Yui et al [75] In both cases, characteristic low-wavenumber shifts of the OH stretching vibrational modes of the interfacial water molecules were observed. Holmlid [76] studied vibrational transitions in Rydberg matter clusters from SRS and Rabi-flopping phase delay in the infrared.…”