Dr John Proctor's Outputs (36)

Subcritical Determination of the Frenkel Line in Liquid Nitrogen, the Emergent Final Picture, and a Universal Equation for the Coordination Number of Real Fluids (2025)
Journal Article

We performed a series of neutron scattering experiments on deeply subcritical liquid nitrogen at 90 K (0.7T C ). Our findings, when taken together with our previous results at 160 K (1.27T C ) and 300 K (2.4T C ), allow the Frenkel line phenomenon to... Read More about Subcritical Determination of the Frenkel Line in Liquid Nitrogen, the Emergent Final Picture, and a Universal Equation for the Coordination Number of Real Fluids.

All-optical method to directly measure the pressure–volume–temperature equation of state of fluids in the diamond anvil cell (2024)
Journal Article
Proctor, J. E., Robertson, C. E. A., Jones, L. J., Phillips, J., Watson, K., Dabburi, Y., & Moss, B. (2024). All-optical method to directly measure the pressure–volume–temperature equation of state of fluids in the diamond anvil cell. Physics of Fluids, 36(8), 087145. https://doi.org/10.1063/5.0220503

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 chamber. Our m... Read More about All-optical method to directly measure the pressure–volume–temperature equation of state of fluids in the diamond anvil cell.

Generally applicable physics-based equation of state for liquids. (2024)
Journal Article
Proctor, J. E., & Trachenko, K. (2024). Generally applicable physics-based equation of state for liquids. Reports on Progress in Physics, 87(9), Article 098001. https://doi.org/10.1088/1361-6633/ad6a80

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 applicable to liqu... Read More about Generally applicable physics-based equation of state for liquids..

Position of the Frenkel Line in supercritical nitrogen at 25°C, 75°C, 100°C and 125°C (2023)
Thesis

The pressure at which the Frenkel line was crossed in supercritical nitrogen was investigated at different temperatures via Raman spectroscopy, using a diamond anvil cell to control pressure and ruby or Sm:YAG as a pressure scale. The results for the... Read More about Position of the Frenkel Line in supercritical nitrogen at 25°C, 75°C, 100°C and 125°C.

A comparison of different Fourier transform procedures for analysis of diffraction data from noble gas fluids (2023)
Journal Article
Proctor, J. E., Pruteanu, C. G., Moss, B., Kuzovnikov, M. A., Ackland, G. J., Monk, C. W., & Anzellini, S. (2023). A comparison of different Fourier transform procedures for analysis of diffraction data from noble gas fluids. Journal of Applied Physics, 134(11), Article 114701. https://doi.org/10.1063/5.0161033

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–Barney mod... Read More about A comparison of different Fourier transform procedures for analysis of diffraction data from noble gas fluids.

Derivation of the Field Due to a Magnetic Dipole Without Use of the Vector Potential (2022)
Journal Article
Proctor, J. E., & Gould, H. T. (2023). Derivation of the Field Due to a Magnetic Dipole Without Use of the Vector Potential. Physics Teacher, 61(1), 40-42. https://doi.org/10.1119/5.0077127

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 undergraduate level... Read More about Derivation of the Field Due to a Magnetic Dipole Without Use of the Vector Potential.

Krypton and the fundamental flaw of the Lennard-Jones Potential (2022)
Journal Article
Pruteanu, C., Loveday, J., Ackland, G., & Proctor, J. (2022). Krypton and the fundamental flaw of the Lennard-Jones Potential. Journal of Physical Chemistry Letters, 13(35), 8284-8289. https://doi.org/10.1021/acs.jpclett.2c02004

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 using Empirica... Read More about Krypton and the fundamental flaw of the Lennard-Jones Potential.

Phase diagram of ethane above 300 K (2022)
Journal Article
Proctor, J., Spender, J., & Gould, H. (2022). Phase diagram of ethane above 300 K. Journal of Physical Chemistry C, 126(26), 10792-10799. https://doi.org/10.1021/acs.jpcc.2c00875

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 solid–solid t... Read More about Phase diagram of ethane above 300 K.

Characterization of the high-pressure and high-temperature phase diagram and equation of state of chromium. (2022)
Journal Article
Anzellini, S., Errandonea, D., Burakovsky, L., Proctor, J., Turnbull, R., & Beavers, C. (2022). Characterization of the high-pressure and high-temperature phase diagram and equation of state of chromium. Scientific reports, 12(1), 6727. https://doi.org/10.1038/s41598-022-10523-2

The high-pressure and high-temperature phase diagram 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, using ab ini... Read More about Characterization of the high-pressure and high-temperature phase diagram and equation of state of chromium..

High pressure photoluminescence of bismuth-doped yttria-alumina-silica glass (2022)
Journal Article

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 NIR emitting... Read More about High pressure photoluminescence of bismuth-doped yttria-alumina-silica glass.

Structural markers of the Frenkel line in the proximity of Widom lines (2021)
Journal Article
Pruteanu, C., Proctor, J., Alderman, O., & Loveday, J. (2021). Structural markers of the Frenkel line in the proximity of Widom lines. Journal of Physical Chemistry B, 125(31), 8902-8906. https://doi.org/10.1021/acs.jpcb.1c04690

We have performed a neutron scattering experiment on supercritical
uid nitrogen
at 160 K (1.27 TC) over a wide pressure range (7.8 MPa / 0.260 g/ml to 125 MPa /
0.805 g/ml). This has enabled us to study the process by which nitrogen changes from... Read More about Structural markers of the Frenkel line in the proximity of Widom lines.

Mechanical properties of graphene (2021)
Journal Article

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, it argues th... Read More about Mechanical properties of graphene.

Modeling of liquid internal energy and heat capacity over a wide pressure–temperature range from first principles (2020)
Journal Article
Proctor, J. (2020). Modeling of liquid internal energy and heat capacity over a wide pressure–temperature range from first principles. Physics of Fluids, 32, 107105. https://doi.org/10.1063/5.0025871

Recently, there have been significant theoretical advances in our understanding of liquids and dense supercritical fluids based on their ability to support high frequency transverse (shear) waves. Here, we have constructed a new computer model using... Read More about Modeling of liquid internal energy and heat capacity over a wide pressure–temperature range from first principles.

The liquid and supercritical fluid states of matter (2020)
Book
Proctor, J. (2020). The liquid and supercritical fluid states of matter. CRC Press (Taylor and Francis). https://doi.org/10.1201/9780429491443

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 and solid-l... Read More about The liquid and supercritical fluid states of matter.

Raman spectroscopy of ethane (C 2 H 6 ) to 120 GPa at 300 K (2020)
Journal Article
Read, L., Spender, J., & Proctor, J. (2020). Raman spectroscopy of ethane (C 2 H 6 ) to 120 GPa at 300 K. Journal of Raman Spectroscopy, 51(11), 2311-2317. https://doi.org/10.1002/jrs.5971

We have conducted a Raman study of solid ethane (C2H6) at pressures up to 120 GPa at 300 K. We observe changes within the ν3 and ν11 Raman‐active vibrational modes providing evidence for several previously unobserved phase transitions at room tempera... Read More about Raman spectroscopy of ethane (C 2 H 6 ) to 120 GPa at 300 K.

Experimental and theoretical confirmation of an orthorhombic phase transition in niobium at high pressure and temperature (2020)
Journal Article

Compared to other body-centered cubic (bcc) transition metals, Nb has been the subject of fewer compression studies and there are still aspects of its phase diagram which are unclear. Here, we report a combined theoretical and experimental study of N... Read More about Experimental and theoretical confirmation of an orthorhombic phase transition in niobium at high pressure and temperature.

Influence of synthesis conditions on the structure of nickel nanoparticles and their reactivity in selective asymmetric hydrogenation (2019)
Journal Article

Unsupported and SiO2-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 structural... Read More about Influence of synthesis conditions on the structure of nickel nanoparticles and their reactivity in selective asymmetric hydrogenation.

Transition from gas-like to liquid-like behavior in supercritical N2 (2019)
Journal Article
Proctor, J., Pruteanu, C., Morrison, I., Crowe, I., & Loveday, J. (2019). Transition from gas-like to liquid-like behavior in supercritical N2. Journal of Physical Chemistry Letters, 10(21), 6584-6589. https://doi.org/10.1021/acs.jpclett.9b02358

We have studied in detail the transition from gas-like to rigid liquidlike 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 observe a narr... Read More about Transition from gas-like to liquid-like behavior in supercritical N2.

Melting curve and phase diagram of vanadium under high-pressure and high-temperature conditions (2019)
Journal Article
Errandonea, D., Macleod, S., Burakovsky, L., Santamaria-Perez, D., Proctor, J., Cynn, H., & Mezouar, M. (2019). Melting curve and phase diagram of vanadium under high-pressure and high-temperature conditions. Physical Review B, 100(9), https://doi.org/10.1103/PhysRevB.100.094111

We report a combined experimental and theoretical study of the melting curve
and the structural behavior of vanadium under extreme pressure and temperature. We
performed powder x-ray diffraction experiments up to 120 GPa and 4000 K, determining
th... Read More about Melting curve and phase diagram of vanadium under high-pressure and high-temperature conditions.

Viewpoint : graphene is thin, but not infinitely so (2019)
Journal Article
Proctor, J. (2019). Viewpoint : graphene is thin, but not infinitely so. Physics - Spotlighting Exceptional Research, 12, 104-104. https://doi.org/10.1103/Physics.12.104

Atomically thin graphene is considered a prototypical 2D material, but high-pressure experiments now reveal the 3D nature of its mechanical properties.