Thermodynamics, compressibility, and phase diagram: Shock compression of supercritical fluid xenon

Zheng, Jun; Chen, Q. F.; Gu, Yu; Chen, Z. Y.; Li, C. J.

doi:10.1063/1.4896071

Cited by 7 publications

(3 citation statements)

References 29 publications

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“…Secondly, at this temperature an incommensurate adlayer in the solid phase for both Ar and Xe adsorbed on the carbon surface is expected, which is confirmed by our calculations (see Fig. 6 (a), (b) and (c)), and other works published in the literature [73][74][75][76][77][78][79][80] . This incommensurate phase is an organized phase for both Ar and Xe whose densities are expected to be homogeneous and high enough to form the solid structures, which explains the compressive strain on the PG.…”

Section: Resultssupporting

confidence: 89%

Probing the interaction of noble gases with pristine and nitrogen-doped graphene through Raman spectroscopy

et al. 2018

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The interactions of adsorbates with graphene have received increasing attention due to its importance in the development of applications involving graphene-based coatings. Here, we present a study of the adsorption of noble gases on pristine and nitrogen-doped graphene. Single-layer graphene samples were synthesized by chemical vapor deposition (CVD) and transferred to transmission electron microscopy (TEM) grids. Several noble gases were allowed to adsorb on the suspended graphene substrate at very low temperatures. Raman spectra show distinct frequency blue shifts in both the 2Dand G-bands, which are induced by gas adsorption onto high quality single layer graphene (1LG). These shifts, which we associate with compressive biaxial strain in the graphene layers induced by the noble gases, are negligible for nitrogen-doped graphene. Additionally, a thermal depinning transition, which is related to the desorption of a noble gas layer from the graphene surface at low temperatures (ranging from 20 to 35K), was also observed at different transition temperatures for different noble gases. These transition temperatures were found to be 25K for Argon and 35K for Xenon. Moreover, we were able to obtain values for the compressive biaxial strain in graphene induced by the adsorbed layer of noble gases, using Raman spectroscopy. Ab initio calculations confirmed the correlation between the noble gas-induced strain and the changes in the Raman features observed.

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Section: Resultssupporting

confidence: 89%

Probing the interaction of noble gases with pristine and nitrogen-doped graphene through Raman spectroscopy

et al. 2018

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“…The solid blue line in figure 11 indicates when the bubble becomes a more ordered solid (characterised by sharper peaks in the RDF). Based on Xe phase diagrams [41,42] the Xe solid phase at 300 K is observed at a pressure of ∼ 0.51 GPa. This agrees well with our observation of solid in the bubble seen above a pressure of 0.44 GPa.…”

Section: Figure 6a Includes Vibrational Entropy Terms Presented In Tablementioning

confidence: 99%

The predicted shapes of voids and Xe bubbles in UO2

Galvin

Rushton

Cooper

et al. 2021

Journal of Nuclear Materials

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Morphology is a fundamental attribute when investigating voids and bubbles in UO 2 . This study uses molecular dynamics and Monte Carlo simulations to predict the lowest energy shapes for voids and bubbles in UO 2 . The energies of the {100}, {110} and {111} surfaces have been calculated and used to predict the equilibrium void shape from Wulff construction. This equilibrium shape is compared to low energy faceted voids exhibiting different relative proportions of each family of terminating surfaces. It is found that the equilibrium Wulff shape does not represent the lowest energy morphology for nm void sizes at temperatures between 300 K and 1200 K. Furthermore, the lowest energy faceted voids are slightly more energetically favourable than spherical voids, and as Xe is added, and bubble pressure increases, the faceted morphology becomes even more favourable than the spherical shape.

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“…For the above reasons, we have chosen to study neutral Xe gas in this work. We consider Xe at a temperature of 300 K, which is above its critical point [68], thereby avoiding liquid droplet formation. In the next section, we will discuss the computational models used for our studies of PIPPs generally, and dense Xe in particular.…”

Section: Introductionmentioning

confidence: 99%

Controllable non-ideal plasmas from photoionized compressed gases

2018

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Based on a suite of molecular dynamics simulations, we propose a strategy for producing non-ideal plasmas with controllable properties over a wide range of densities between those of ultracold neutral plasmas and those of solid-density plasmas. We simulated the formation of non-equilibrium plasmas from photoionized, cool gases that are spatially precorrelated through neutral-neutral interactions that are important at moderate-to-high pressures. A wide range of physical properties, including Coulomb collisional rates, partial pressures, screening strengths, continuum lowering, interspecies Coulomb coupling, electron degeneracy and ionization states, were characterized across more than an order of magnitude variation in the initial gas pressure. A wide range of plasma properties are also found to vary when the initial pressure of a precorrelated gas is varied. Thus, we propose that nonideal plasmas with tunable properties can be generated by photo-ionizing a dense, precorrelated gas. We find that the optimal initial density range for the gas is near a Kirkwood/Widom-Fisher line in the neutral-gas phase diagram. This strategy for generating non-ideal plasmas suggests experiments that have significant advantages over both ultracold and solid-density plasma experiments because the collisional, collective and recombination timescales can be tuned across many orders of magnitude, potentially allowing for a wider range of diagnostics. Moreover, the added costs of cooling ultracold plasmas and diagnosing dense matter with x-rays are eliminated. two-temperature variations (i.e., separate electron and ion temperatures). The desired method would allow for systematic control of plasma properties, including transport and relaxation, ionization-potential depression (IPD), the non-ideal multi-temperature equation of state (EOS), and screening involving strongly coupled electrons. Transport properties [43,44] and relaxation processes [45][46][47][48] are important to validate and model dense plasma experiments. The advent of XFEL [49-51] has renewed interest in IPD (a.k.a.'continuum lowering'), and dense plasma experiments have been used to validate different IPD models [52][53][54][55]. An accurate EOS is essential for examining plasma evolution on the hydrodynamic scale, such as the evolution of fluid instabilities in ICF experiments [56,57] or UCNP expansion into a vacuum [29]. Strongly coupled electrons, which are difficult to create at high densities because of degeneracy, have been of theoretical and experimental interest for several decades [21,22], including, more recently, for their role in the conductance of liquid-helium surfaces [23]. Finally, such an approach could also serve as a platform for measuring coupled electron-ion modes, which have been of recent interest in dense two-temperature plasmas [58]. In fact, isolated experiments at these intermediate densities have been performed successfully [59-61]; however, controllability and tunability of plasma properties were not the focus of those experiments. Here, we pr...

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Thermodynamics, compressibility, and phase diagram: Shock compression of supercritical fluid xenon

Cited by 7 publications

References 29 publications

Probing the interaction of noble gases with pristine and nitrogen-doped graphene through Raman spectroscopy

Probing the interaction of noble gases with pristine and nitrogen-doped graphene through Raman spectroscopy

The predicted shapes of voids and Xe bubbles in UO2

Controllable non-ideal plasmas from photoionized compressed gases

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