Sonoluminescence from OH(C2Σ+) and OH(A2Σ+) Radicals in Water: Evidence for Plasma Formation during Multibubble Cavitation

Pflieger, Rachel; Brau, Henri‐Pierre; Nikitenko, Sergey I.

doi:10.1002/chem.201002170

Cited by 48 publications

(50 citation statements)

References 24 publications

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“…Sonoluminescence studies have suggested that hydrated OH in the A and C states exhibits an emission in a similar spectral range, with an onset near 200 nm and extending to above 400 nm. 34,35 The spectrum recorded in our work differs however in shape and width, and there seems to be no obvious correspondence to the sonoluminescence spectra. Note that the low-energy onset of band III in the emission spectrum cannot be accurately determined from the present data because for all wavelengths above 340 nm emission contributions from first and second order of the spectrometer overlap, and cannot be separated with the present setup.…”

Section: Resultscontrasting

confidence: 60%

Optical Fluorescence Detected from X-ray Irradiated Liquid Water

et al. 2017

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Despite its importance, the structure and dynamics of liquid water are still poorly understood in many apsects. Here, we report on the observation of optical fluorescence upon soft X-ray irradiation of liquid water. Detection of spectrally resolved fluorescence was achieved by a combination of the liquid microjet technique and fluorescence spectroscopy. We observe a genuine liquid-phase fluorescence manifested by a broad emission band in the 170 to 340 nm (4-7 eV) photon wavelength range. In addition, another narrower emission near 300 nm can be assigned to the fluorescence of OH(A state) in the gas phase, the emitting species being formed by Auger electrons escaping from liquid water. We argue that the newly observed broad-band emission of liquid water is relevant in search of extraterrestrial life, and we also envision the observed electronejection mechanism to find application for exploring solutes at liquid-vapor interfaces.

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Section: Resultscontrasting

confidence: 60%

Optical Fluorescence Detected from X-ray Irradiated Liquid Water

et al. 2017

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“…The most probable mechanism of OH(C 2 Σ + ) species production involves electron impact of water molecules. It was concluded that the observation of OH(C 2 Σ + -A 2 Σ + ) emission indicates the formation of nonthermal plasma inside the cavitation bubble [44]. Spectroscopic analysis of OH(A 2 Σ + -X 2 Π i ) vibrational transitions supports this hypothesis [22].…”

Section: Sonoluminescence As a Probe Of Intrabubble Conditionsmentioning

confidence: 90%

“…• recombination, water molecule de-excitation, and OH(B 2 Σ + -A 2 Σ) emission [22,44]. Figure 1 shows the experimental SL spectra in argon measured at different ultrasonic frequencies normalized on the most intense OH( (0-6; 0-7; 0-8; 0-9)…”

Section: Sonoluminescence As a Probe Of Intrabubble Conditionsmentioning

confidence: 99%

Plasma Formation during Acoustic Cavitation: Toward a New Paradigm for Sonochemistry

Nikitenko

2014

Advances in Physical Chemistry

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The most recent spectroscopic studies of single bubble (SBSL) and multibubble (MBSL) sonoluminescence reveal that the origin of extreme intrabubble conditions is related to nonequilibrium plasma formed inside the collapsing bubbles. Analysis of the relative populations of OH(A 2 Σ + ) vibrational states observed during MBSL in water saturated with noble gases shows that in the presence of argon at low ultrasonic frequency weakly excited plasma is formed. At high-frequency ultrasound the plasma inside the collapsing bubbles exhibits Treanor behavior typical for strong vibrational excitation. Plasma formation during SBSL was observed in concentrated H 2 SO 4 preequilibrated with Ar. The light emission spectra exhibit the lines from excited Ar atoms and ionized oxygen O 2 + . Formation of O 2 + species is inconsistent with any thermal process. Furthermore, the SBSL spectra in H 2 SO 4 show emission lines from Xe + , Kr + , and Ar + in full agreement with plasma hypothesis. The photons and the "hot" particles generated by cavitation bubbles enable the excitation of nonvolatile species in solutions increasing their chemical reactivity. Secondary sonochemical products may arise from chemically active species that are formed inside the bubble but then diffuse into the liquid phase and react with solution precursors to form a variety of products.

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“…As can be seen in Figure 4 ]~0.001 M is related to uranium self-absorption that decreases the intensity at higher concentrations (see Ref. 3 ).…”

Section: Representative Resultsmentioning

confidence: 94%

Activating Molecules, Ions, and Solid Particles with Acoustic Cavitation

Pflieger

Chave

Virot

et al. 2014

JoVE

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The chemical and physical effects of ultrasound arise not from a direct interaction of molecules with sound waves, but rather from the acoustic cavitation: the nucleation, growth, and implosive collapse of microbubbles in liquids submitted to power ultrasound. The violent implosion of bubbles leads to the formation of chemically reactive species and to the emission of light, named sonoluminescence. In this manuscript, we describe the techniques allowing study of extreme intrabubble conditions and chemical reactivity of acoustic cavitation in solutions. The analysis of sonoluminescence spectra of water sparged with noble gases provides evidence for nonequilibrium plasma formation. The photons and the "hot" particles generated by cavitation bubbles enable to excite the non-volatile species in solutions increasing their chemical reactivity. For example the mechanism of ultrabright sonoluminescence of uranyl ions in acidic solutions varies with uranium concentration: sonophotoluminescence dominates in diluted solutions, and collisional excitation contributes at higher uranium concentration. Secondary sonochemical products may arise from chemically active species that are formed inside the bubble, but then diffuse into the liquid phase and react with solution precursors to form a variety of products. For instance, the sonochemical reduction of Pt(IV) in pure water provides an innovative synthetic route for monodispersed nanoparticles of metallic platinum without any templates or capping agents. Many studies reveal the advantages of ultrasound to activate the divided solids. In general, the mechanical effects of ultrasound strongly contribute in heterogeneous systems in addition to chemical effects. In particular, the sonolysis of PuO 2 powder in pure water yields stable colloids of plutonium due to both effects. Video LinkThe video component of this article can be found at

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Sonoluminescence from OH(C²Σ⁺) and OH(A²Σ⁺) Radicals in Water: Evidence for Plasma Formation during Multibubble Cavitation

Cited by 48 publications

References 24 publications

Optical Fluorescence Detected from X-ray Irradiated Liquid Water

Optical Fluorescence Detected from X-ray Irradiated Liquid Water

Plasma Formation during Acoustic Cavitation: Toward a New Paradigm for Sonochemistry

Activating Molecules, Ions, and Solid Particles with Acoustic Cavitation

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