Probing high-pressure reactions in heterogeneous materials by Raman spectroscopy

Ceppatelli, Matteo; Gorelli, Federico A.; Haines, J.; Santoro, Mario; Bini, Roberto

doi:10.1515/zkri-2013-1627

Cited by 13 publications

(11 citation statements)

References 33 publications

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“…Raman measurements were performed by using the 647.1 nm line of a Kr + laser as the excitation source. The backscattering geometry was used through a long working distance, 20× Mitutoyo micro-objective providing a beam spot of 2–3 μm, and the unpolarized scattered light was detected by a single monochromator (Acton/SpectraPro 2500i) equipped with holographic super notch filters and a CCD detector (Princeton Instruments Spec-10:100BR) . The typical spectral resolution was 1 cm –1 for IR and 0.6 cm –1 for Raman measurements.…”

Section: Experimental Methodsmentioning

confidence: 99%

Dense, Subnano Phase of Clustered O₂

et al. 2019

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Condensed O2 tends to form clusters, even with a long-range order. In particular, in solid oxygen, strong intermolecular charge transfer at high pressures leads to the formation of (O2)4 tetramers above 10 GPa, in the ε-O2 phase, with weak O2–O2 chemical bonds. Indeed, ε-O2 is entirely made of these tetramers. We conducted experimental investigations on strongly densified O2 in a different environment, that is to say in the form of a subnano phase build up within the 1D microchannels of a purely siliceous, inert zeolite, TON, at pressures of 0.5–20 GPa, by means of diamond anvil cells. Our X-ray diffraction and infrared and Raman spectroscopy results consistently show that oxygen forms clusters in this nanophase, above 10 GPa, similar to ε-O2, except that the clusters are rather of the type of weakly bonded (O2)2 dimers in this case. Also, by analogy with bulk oxygen, we show that the O2 spin within the dimers departs from S = 1 toward lower values, upon increasing pressure. Our findings thereby add to the general view on essential properties of highly dense oxygen.

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Section: Experimental Methodsmentioning

confidence: 99%

Dense, Subnano Phase of Clustered O₂

et al. 2019

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“…Raman spectra were performed using the 647.1 nm line of a Kr + laser as the excitation source. Backscattering geometry was used with X20 Mitutoyo micro-objective giving a laser spot of <3 μm, and the sample signal was detected with an Acton/SpectraPro 2500i single monochromator with a total resolution, including laser linewidth, of ∼0.6 cm –1 , equipped with holographic super notch filters and a CCD detector (Princeton Instruments Spec-10:100 BR) . Meshes of typically 3 × 3 equally spaced points with 20–30 μm spacing were measured for each pressure with an integration time of 300–600 s per point.…”

Section: Methodsmentioning

confidence: 99%

Intermolecular Interactions in Highly Disordered, Confined Dense N₂

Santoro

Gorelli

Bini

et al. 2017

J. Phys. Chem. Lett.

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Molecular nitrogen is a benchmark system for condensed matter and, in particular, for looking at universal properties of strongly confined dense systems. We conducted Raman and X-ray diffraction measurements on a dense and disordered form of molecular nitrogen subnanoconfined in a noncatalytic pure SiO zeolite under pressure, up to 50 GPa. In this form, N-N interactions and, consequently, distances are found to be very close to those of bulk N and intramolecular interactions progressively weaken upon increasing pressure. Surprisingly, the filled zeolite is still crystalline at 50 GPa with silicon in tetrahedral coordination by oxygen, which is a record pressure for this type of coordination among all the known forms of silica. We have thus found a rationale for the polymerization of a number molecules occurring in the microchannels of noncatalytic zeolites under pressure, where the pressure threshold is found to be very similar to that observed in bulk samples.

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“…33 Raman signals were excited by the 647.1 nm line of a Kr + laser. Backscattering geometry was used through a 20× Mitutoyo micro-objective providing a beam spot of 2−3 μm, and the scattered light was detected by a single monochromator (Acton/SpectraPro 2500i) equipped with super notch filters and a charge-coupled device (CCD) detector (Princeton Instruments Spec-10:100BR) 34 with a typical spectral resolution of 0.6 cm −1 .…”

Section: Experimental and Theoretical Methodsmentioning

confidence: 99%

Insertion of Oxygen and Nitrogen in the Siliceous Zeolite TON at High Pressure

Santoro

Morana²,

Scelta

et al. 2021

J. Phys. Chem. C

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The insertion of oxygen and nitrogen molecules in the one-dimensional (1D) pore system of the zeolite TON was studied at high pressure by vibrational spectroscopy, X-ray diffraction, and Monte Carlo (MC) molecular modeling. Rietveld refinements and MC modeling indicate that, on average, six diatomic molecules per unit cell enter the pores of the zeolite. This induces changes in compressibility and distortion related to the Cmc2 1 -to-Pbn2 1 phase transition compared to the empty-pore material. The filling behavior with N 2 and O 2 under pressure is similar to that of argon, suggesting that the kinetic diameter, which is very close in these three systems, plays a major role. The orientation of the diatomic molecules appears to have a rather minor effect on filling occurring at a slightly higher pressure for N 2 , which has a larger kinetic diameter. Both inserted molecules, initially not showing any marked orientation, begin to exhibit a degree of orientational order above 2 GPa.

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Probing high-pressure reactions in heterogeneous materials by Raman spectroscopy

Cited by 13 publications

References 33 publications

Dense, Subnano Phase of Clustered O₂

Dense, Subnano Phase of Clustered O₂

Intermolecular Interactions in Highly Disordered, Confined Dense N₂

Insertion of Oxygen and Nitrogen in the Siliceous Zeolite TON at High Pressure

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Probing high-pressure reactions in heterogeneous materials by Raman spectroscopy

Cited by 13 publications

References 33 publications

Dense, Subnano Phase of Clustered O2

Dense, Subnano Phase of Clustered O2

Intermolecular Interactions in Highly Disordered, Confined Dense N2

Insertion of Oxygen and Nitrogen in the Siliceous Zeolite TON at High Pressure

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Product

Resources

About

Dense, Subnano Phase of Clustered O₂

Dense, Subnano Phase of Clustered O₂

Intermolecular Interactions in Highly Disordered, Confined Dense N₂