John E. Proctor
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View article: Subcritical Determination of the Frenkel Line in Liquid Nitrogen, the Emergent Final Picture, and a Universal Equation for the Coordination Number of Real Fluids
Subcritical Determination of the Frenkel Line in Liquid Nitrogen, the Emergent Final Picture, and a Universal Equation for the Coordination Number of Real Fluids Open
We performed a series of neutron scattering experiments on deeply subcritical liquid nitrogen at 90 K (0.7TC). Our findings, when taken together with our previous results at 160 K (1.27TC) and 300 K (2.4TC), allow the Frenkel line phenomen…
View article: Generally applicable physics-based equation of state for liquids
Generally applicable physics-based equation of state for liquids Open
Physics-based first-principles pressure-volume-temperature equations of state (EOS) exist for solids and gases but not for liquids due to the long-standing fundamental problems involved in liquid theory. Current EOS models that are applica…
View article: All-optical method to directly measure the pressure-volume-temperature equation of state of fluids in the diamond anvil cell
All-optical method to directly measure the pressure-volume-temperature equation of state of fluids in the diamond anvil cell Open
We have developed a new all-optical method to directly measure the pressure-volume-temperature (PVT) equation of state (EOS) of fluids and transparent solids in the diamond anvil high pressure cell by measuring the volume of the sample cha…
View article: A comparison of different Fourier transform procedures for analysis of diffraction data from noble gas fluids
A comparison of different Fourier transform procedures for analysis of diffraction data from noble gas fluids Open
A comparison is made between the three principal methods for the analysis of neutron and x-ray diffraction data from noble gas fluids by direct Fourier transform. All three methods (standard Fourier transform, Lorch modification, and Soper…
View article: Derivation of the Field Due to a Magnetic Dipole Without Use of the Vector Potential
Derivation of the Field Due to a Magnetic Dipole Without Use of the Vector Potential Open
The mathematical form of the magnetic field due to a current loop, and the fact that it is identical to the electric field due to an electric dipole in the far field, are fundamental to our understanding of electromagnetism. While undergra…
View article: Krypton and the Fundamental Flaw of the Lennard-Jones Potential
Krypton and the Fundamental Flaw of the Lennard-Jones Potential Open
We have performed a series of neutron scattering experiments on supercritical krypton. Our data and analysis allow us to characterize the Frenkel line crossover in this model monatomic fluid. The data from our measurements was analyzed usi…
View article: Phase Diagram of Ethane above 300 K
Phase Diagram of Ethane above 300 K Open
We have measured the melting curve of ethane from 300 to 450 K. Our results indicate that to describe all melting curve data above the triple point, it is necessary to account for a kink in the melting curve where the phase III–phase IV so…
View article: High pressure photoluminescence of bismuth-doped yttria-alumina-silica glass
High pressure photoluminescence of bismuth-doped yttria-alumina-silica glass Open
We report the effects of high pressure, up to 10.45 GPa, on the photoluminescence of Bi-doped yttria-alumina-silica (Bi:YAlSi) glass under 532 nm excitation. We identify three emission bands attributed to Bi3+, Bi+ and the controversial NI…
View article: Characterization of the High-Pressure and High-Temperature Phase Diagram and Equation of State of Chromium
Characterization of the High-Pressure and High-Temperature Phase Diagram and Equation of State of Chromium Open
The high-pressure and high-temperature melting curve of chromium has been investigated both experimentally (in situ), using a laser-heated diamond-anvil cell technique coupled with synchrotron powder X-ray diffraction, and theoretically, u…
View article: Structural Markers of the Frenkel Line in the Proximity of Widom Lines
Structural Markers of the Frenkel Line in the Proximity of Widom Lines Open
We have performed a neutron scattering experiment on supercritical fluid nitrogen at 160 K (1.27 TC) over a wide pressure range (7.8 MPa/0.260 g/mL-125 MPa/0.805 g/mL). This has enabled us to study the process by which nitrogen changes fro…
View article: Mechanical properties of graphene
Mechanical properties of graphene Open
This paper reviews the mechanical properties of graphene with particular attention to what is established and what is still uncertain. It clarifies the thickness and the elastic constants, and by also considering also phonon frequencies, i…
View article: Raman spectroscopy of ethane (C<sub>2</sub>H<sub>6</sub>) to 120 GPa at 300 K
Raman spectroscopy of ethane (C<sub>2</sub>H<sub>6</sub>) to 120 GPa at 300 K Open
We have conducted a Raman study of solid ethane (C 2 H 6 ) at pressures up to 120 GPa at 300 K. We observe changes within the ν 3 and ν 11 Raman‐active vibrational modes providing evidence for several previously unobserved phase transition…
View article: The Liquid and Supercritical Fluid States of Matter
The Liquid and Supercritical Fluid States of Matter Open
This book addresses graduate students and researchers wishing to better understand the liquid and supercritical fluid states of matter, presenting a single cohesive treatment of the liquid and supercritical fluid states using the gas-like …
View article: Influence of Synthesis Conditions on the Structure of Nickel Nanoparticles and their Reactivity in Selective Asymmetric Hydrogenation
Influence of Synthesis Conditions on the Structure of Nickel Nanoparticles and their Reactivity in Selective Asymmetric Hydrogenation Open
Unsupported and SiO 2 ‐supported Ni nanoparticles (NPs) were synthesised via hot‐injection colloidal route using oleylamine (OAm) and trioctylphosphine (TOP) as reducing and protective agents, respectively. By adopting a multi‐length scale…
View article: Transition from Gas-like to Liquid-like Behavior in Supercritical N<sub>2</sub>
Transition from Gas-like to Liquid-like Behavior in Supercritical N<sub>2</sub> Open
We have studied in detail the transition from gas-like to rigid liquid-like behavior in supercritical N2 at 300 K (2.4 TC). Our study combines neutron diffraction and Raman spectroscopy with ab initio molecular dynamics simulations. We obs…
View article: Melting curve and phase diagram of vanadium under high-pressure and high-temperature conditions
Melting curve and phase diagram of vanadium under high-pressure and high-temperature conditions Open
We discuss melting curve and phase diagram of vanadium under high-pressure and high-temperature conditions We report a combined experimental and theoretical study of the melting curve and the structural behavior of vanadium under extreme p…
View article: On the transition from gas-like to liquid-like behaviour in supercritical N2
On the transition from gas-like to liquid-like behaviour in supercritical N2 Open
We have studied in detail the transition from gas-like to rigid liquid-like behaviour in supercritical $N_2$ at 300 K (2.4 $T_C$). Our study combines neutron diffraction and Raman spectroscopy with empirical potential structure refinement …
View article: Graphene Is Thin, but Not Infinitely So
Graphene Is Thin, but Not Infinitely So Open
Atomically thin graphene is considered a prototypical 2D material, but high-pressure experiments now reveal the 3D nature of its mechanical properties.
View article: Observation of Liquid–Liquid Phase Transitions in Ethane at 300 K
Observation of Liquid–Liquid Phase Transitions in Ethane at 300 K Open
We have conducted Raman spectroscopy experiments on liquid ethane (C2H6) at 300 K, obtaining a large amount of data at very high resolution. This has enabled the observation of Raman peaks expected but not previously observed in liquid eth…
View article: Electric discharge machine for preparation of diamond anvil cell sample chambers
Electric discharge machine for preparation of diamond anvil cell sample chambers Open
We have designed and constructed a novel electric discharge machine designed primarily for the preparation of sample chambers in rhenium and stainless steel gaskets for diamond anvil cell experiments. Our design combines automatic stage mo…
View article: High Pressure Raman, Optical Absorption, and Resistivity Study of SrCrO<sub>4</sub>
High Pressure Raman, Optical Absorption, and Resistivity Study of SrCrO<sub>4</sub> Open
We studied the electronic and vibrational properties of monazite-type SrCrO4 under compression. The study extended the pressure range of previous studies from 26 to 58 GPa. The existence of two previously reported phase transitions was con…
View article: Dynamics, thermodynamics and structure of liquids and supercritical fluids: crossover at the Frenkel line
Dynamics, thermodynamics and structure of liquids and supercritical fluids: crossover at the Frenkel line Open
We review recent work aimed at understanding dynamical and thermodynamic properties of liquids and supercritical fluids. The focus of our discussion is on solid-like transverse collective modes, whose evolution in the supercritical fluids …
View article: Raman spectroscopy of methane (CH<sub>4</sub>) to 165 GPa: Effect of structural changes on Raman spectra
Raman spectroscopy of methane (CH<sub>4</sub>) to 165 GPa: Effect of structural changes on Raman spectra Open
We have conducted a Raman study of methane (CH 4 ), a major constituent of the outer planets, at pressures up to 165 GPa. We observe splitting of the principal Raman‐active vibrational mode above 45 GPa and a nonlinear dependence of Raman …
View article: On the high-pressure phase stability and elastic properties of<i>β</i>-titanium alloys
On the high-pressure phase stability and elastic properties of<i>β</i>-titanium alloys Open
We have studied the compressibility and stability of different β-titanium alloys at high pressure, including binary Ti-Mo, Ti-24Nb-4Zr-8Sn (Ti2448) and Ti-36Nb-2Ta-0.3O (gum metal). We observed stability of the β phase in these alloys to 4…
View article: Determining molecular orientation<i>via</i>single molecule SERS in a plasmonic nano-gap
Determining molecular orientation<i>via</i>single molecule SERS in a plasmonic nano-gap Open
Through combining single molecule SERS measurements, DFT and FDTD calculations, the molecular orientation within the plasmonic nano-gap is recovered.
View article: Comment on: "The Frenkel Line: a direct experimental evidence for the new thermodynamic boundary"
Comment on: "The Frenkel Line: a direct experimental evidence for the new thermodynamic boundary" Open
In a recent publication (D. Bolmatov et al. Sci.Rep. 5, 15850 (2015)) the experimental observation of structural transformations on crossing the Frenkel line in supercritical argon is claimed. Here we show that no experimental evidence of …