EHPRG: The European High Pressure Research Group

## Welcome

Welcome to the official website of the European High Pressure Research Group (EHPRG).

EHPRG is non-profitable academic association established in 1963 which is devoted to science and technology of matter under high pressure. It organizes an annual meeting which brings together hundreds of scientists of various fields, mainly physics, chemistry, Earth and planetary sciences, bio- and food science and technology.

The reasonable size of the group, low conference fees, and a friendly relationship between the attendants have made EHPRG meetings a major event in the European high-pressure community for more than half a century.

## Upcoming high pressure meetings

The current COVID pandemic has led to the cancellation of numerous scientific conferences over the last year, including the 2020 GRC and GRS high-pressure conferences, and the combined AIRAPT/EHPRG-2021 conference that was to be held in Edinburgh this summer. The negative effects of this are being most keenly felt by younger researchers, who have missed golden opportunities to present both their work, and themselves, to the rest of the community.
This online conference aims to address this, by providing up to 360 20-minute oral presentations in which young and early career researchers in our field to present their research to the rest of our international community. Such researchers will be offered the great majority of these slots, complemented by some didactic talks from more established researchers and facility operators. Everyone in the high-pressure community is welcome to attend.
CESC-2021 will be chaired by Malcolm McMahon.

## Upcoming EHPRG Meeting

The Joint 28th AIRAPT and 60th EHPRG International Conference on High Pressure Science and Technology (AIRAPT-2021), originally scheduled for July 2021, has been postponed, and will be held in Edinburgh, UK, in 2023. Exact dates will be announced as soon as possible. AIRAPT-21 will be chaired by Malcolm McMahon (CSEC and University of Edinburgh, UK).
In spite of the Joint AIRAPT-EHPRG Conference, an online Conference on Science at Extreme Conditions will take place in 2021. This online event will have a special focus on young and early career researchers. This will NOT be an AIRAPT/EHPRG conference, but the organizers expect to be able to offer up to 360 slots for 20-minute, and 5-minute “lightning”, oral presentations, spread over 5 days, each of which will have two 2-hour time slots (11am-1pm and 3-5pm UK time), timed so as to provide “office hours” access to speakers from Asia/Europe and Americas/Europe, respectively. Each 2-hour time slot will host up to 6 parallel sessions. The great majority of the available slots for talks will be given to young researchers, complemented by some didactic presentations from more established researchers and facility providers. Everyone in the high-pressure community is welcome to attend.

Selection of high-pressure related titles from top scientific journals.

Regularities of non-stationary diffusion growth of overcritical gas bubbles and kinetics of bubble distribution in presence of capillary and viscous forces
by Anatoly E. Kuchma
The Journal of Chemical Physics, Volume 154, Issue 14, April 2021.
The regularities of non-stationary diffusion growth of overcritical gas bubbles and kinetics of their distribution in sizes in a supersaturated-by-gas liquid solution on the nucleation stage have been analytically described by taking into account the full-scale influence of viscous and capillary forces on pressure in the overcritical bubbles. The results are general and not limited by values of gas supersaturation and gas solubility in the surrounding liquid solution. It is shown how the nonuniform concentration profile of the dissolved gas in supersaturated solution around the growing bubble changes with time and distance from the center of the overcritical bubble and gradually transforms into a stationary (at low solubility and moderate supersaturation of the dissolved gas) or self-similar profile (at large solubility and supersaturation of the dissolved gas). The kinetic theory of the nucleation stage with the excluded volume has been extended to the case of non-stationary gas concentration profiles due to viscous and capillary forces. The general approach has been illustrated in the limiting case of negligible viscous but significant capillary contributions to the vapor pressure in the bubble and in the case when the approximation of the mean field of gas supersaturation can be applied.
8 Apr 2021 at 4:31am
Solvation of simple ions in water at extreme conditions
by Viktor Rozsa
The Journal of Chemical Physics, Volume 154, Issue 14, April 2021.
The interaction of ions and water at high pressure and temperature plays a critical role in Earth and planetary science yet remains poorly understood. Aqueous fluids affect geochemical properties ranging from water phase stability to mineral solubility and reactivity. Here, we report first-principles molecular dynamics simulations of mono-valent ions (Li+, K+, Cl−) as well as NaCl in liquid water at temperatures and pressures relevant to the Earth’s upper mantle (11 GPa, 1000 K) and concentrations in the dilute limit (0.44–0.88 m), in the regime of ocean salinity. We find that, at extreme conditions, the average structural and vibrational properties of water are weakly affected by the presence of ions, beyond the first solvation shell, similar to what was observed at ambient conditions. We also find that the ionic conductivity of the liquid increases in the presence of ions by less than an order of magnitude and that the dielectric constant is moderately reduced by at most ∼10% at these conditions. Our findings may aid in the parameterization of deep earth water models developed to describe water–rock reactions.
8 Apr 2021 at 4:43am
Molecular dynamics study of water confined in MIL-101 metal–organic frameworks
by Shubo Fei
The Journal of Chemical Physics, Volume 154, Issue 14, April 2021.
Molecular dynamics simulations of water adsorbed in Material Institute Lavoisier MIL-101(Cr) metal–organic frameworks are performed to analyze the kinetic properties of water molecules confined in the framework at 298.15 K and under different vapor pressures and clarify the water adsorption mechanism in MIL-101(Cr). The terahertz frequency-domain spectra (THz-FDS) of water are calculated by applying fast Fourier transform to the configurational data of water molecules. According to the characteristic frequencies in the THz-FDS, the dominant motions of water molecules in MIL-101(Cr) can be categorized into three types: (1) low-frequency translational motion (0–0.5 THz), (2) medium-frequency vibrational motion (2–2.5 THz), and (3) high-frequency vibrational motion (>6 THz). Each type of water motion is confirmed by visualizing the water configuration in MIL-101(Cr). The ratio of the number of water molecules with low-frequency translational motion to the total number of water molecules increases with the increase in vapor pressure. In contrast, that with medium-frequency vibrational motion is found to decrease with vapor pressure, exhibiting a pronounced decrease after water condensation has started in the cavities. That with the high-frequency vibrational motion is almost independent of the vapor pressure. The interactions between different types of water molecules affect the THz-FDS. Furthermore, the self-diffusion coefficient and the velocity auto-correlation function are calculated to clarify the adsorption state of the water confined in MIL-101(Cr). To confirm that the general trend of the THz-FDS does not depend on the water model, the simulations are performed using three water models, namely, rigid SPC/E, flexible SPC/E, and rigid TIP5PEw.
12 Apr 2021 at 12:16pm
Phase relations and thermoelasticity of magnesium silicide at high pressure and temperature
by Nico Alexander Gaida
The Journal of Chemical Physics, Volume 154, Issue 14, April 2021.
Within the exploration of sustainable and functional materials, narrow bandgap magnesium silicide semiconductors have gained growing interest. Intriguingly, squeezing silicides to extreme pressures and exposing them to non-ambient temperatures proves fruitful to study the structural behavior, tune the electronic structure, or discover novel phases. Herein, structural changes and thermoelastic characteristics of magnesium silicides were probed with synchrotron x-ray diffraction techniques using the laser-heated diamond anvil cell and large volume press at high pressure and temperature and temperature-dependent synchrotron powder diffraction. Probing the ambient phase of Mg2Si (anti-CaF2-type Mg2Si, space group: Fm[math]m) at static pressures of giga-Pascals possibly unveiled the transformation to metastable orthorhombic anti-PbCl2-type Mg2Si (Pnma). Interestingly, heating under pressures introduced the decomposition of Mg2Si to hexagonal Mg9Si5 (P63) and minor Mg. Using equations of state (EoS), which relate pressure to volume, the bulk moduli of anti-CaF2-type Mg2Si, anti-PbCl2-type Mg2Si, and Mg9Si5 were determined to be B0 = 47(2) GPa, B0 ≈ 72(5) GPa, and B0 = 58(3) GPa, respectively. Employing a high-temperature EoS to the P–V–T data of anti-CaF2-type Mg2Si provided its thermoelastic parameters: BT0 = 46(3) GPa, B′T0 = 6.1(8), and (∂BT0/∂T)P = −0.013(4) GPa K−1. At atmospheric pressure, anti-CaF2-type Mg2Si kept stable at T = 133–723 K, whereas Mg9Si5 transformed to anti-CaF2-type Mg2Si and Si above T ≥ 530 K. This temperature stability may indicate the potential of Mg9Si5 as a mid-temperature thermoelectric material, as suggested from previous first-principles calculations. Within this realm, thermal models were applied, yielding thermal expansion coefficients of both silicides together with estimations of their Grüneisen parameter and Debye temperature.
8 Apr 2021 at 5:05am
Monoclinic ${\mathrm{EuSn}}_{2}{\mathrm{As}}_{2}$: A Novel High-Pressure Network Structure
by Lin Zhao, Changjiang Yi, Chang-Tian Wang, Zhenhua Chi, Yunyu Yin, Xiaoli Ma, Jianhong Dai, Pengtao Yang, Binbin Yue, Jinguang Cheng, Fang Hong, Jian-Tao Wang, Yonghao Han, Youguo Shi, and Xiaohui Yu
Author(s): Lin Zhao, Changjiang Yi, Chang-Tian Wang, Zhenhua Chi, Yunyu Yin, Xiaoli Ma, Jianhong Dai, Pengtao Yang, Binbin Yue, Jinguang Cheng, Fang Hong, Jian-Tao Wang, Yonghao Han, Youguo Shi, and Xiaohui Yu

The layered crystal of ${\mathrm{EuSn}}_{2}{\mathrm{As}}_{2}$ has a ${\mathrm{Bi}}_{2}{\mathrm{Te}}_{3}$-type structure in rhombohedral ($R\overline{3}m$) symmetry and has been confirmed to be an intrinsic magnetic topological insulator at ambient conditions. Combining ab initio calculations and in ...

[Phys. Rev. Lett. 126, 155701] Published Tue Apr 13, 2021
13 Apr 2021 at 12:00pm
Friction on Ice: How Temperature, Pressure, and Speed Control the Slipperiness of Ice
by Rinse W. Liefferink, Feng-Chun Hsia, Bart Weber, and Daniel Bonn
Author(s): Rinse W. Liefferink, Feng-Chun Hsia, Bart Weber, and Daniel Bonn

A new approach for studying friction on ice helps explain why the ease of sliding depends strongly on temperature, contact pressure, and speed.

[Phys. Rev. X 11, 011025] Published Mon Feb 08, 2021
8 Feb 2021 at 11:00am
Emergent Magnetic Phases in Pressure-Tuned van der Waals Antiferromagnet ${\mathrm{FePS}}_{3}$
by Matthew J. Coak, David M. Jarvis, Hayrullo Hamidov, Andrew R. Wildes, Joseph A. M. Paddison, Cheng Liu, Charles R. S. Haines, Ngoc T. Dang, Sergey E. Kichanov, Boris N. Savenko, Sungmin Lee, Marie Kratochvílová, Stefan Klotz, Thomas C. Hansen, Denis P. Kozlenko, Je-Geun Park, and Siddharth S. Saxena
Author(s): Matthew J. Coak, David M. Jarvis, Hayrullo Hamidov, Andrew R. Wildes, Joseph A. M. Paddison, Cheng Liu, Charles R. S. Haines, Ngoc T. Dang, Sergey E. Kichanov, Boris N. Savenko, Sungmin Lee, Marie Kratochvílová, Stefan Klotz, Thomas C. Hansen, Denis P. Kozlenko, Je-Geun Park, and Siddharth S. Saxena

High-pressure neutron studies of so-called magnetic graphene unveil exotic new states and behaviors as the material transitions from an insulator to a metal when compressed.

[Phys. Rev. X 11, 011024] Published Fri Feb 05, 2021
5 Feb 2021 at 11:00am
Pressure-induced yttrium oxides with unconventional stoichiometries and novel properties
by Qiuping Yang, Jianyan Lin, Fei Li, Jing Zhang, Eva Zurek, and Guochun Yang
Author(s): Qiuping Yang, Jianyan Lin, Fei Li, Jing Zhang, Eva Zurek, and Guochun Yang

The oxygenic motifs (e.g., ${\mathrm{O}}^{2–}$, ${{\mathrm{O}}_{2}}^{2\text{–}}$ ${{\mathrm{O}}_{2}}^{2\text{–}}$, and ${{\mathrm{O}}_{2}}^{\text{–}}$) that are present in compounds have a substantial effect on their electronic structure and behavior. Herein, first-principles swarm-intelligence crys...

[Phys. Rev. Materials 5, 044802] Published Fri Apr 09, 2021
9 Apr 2021 at 12:00pm
Latent heat method to detect melting and freezing of metals at megabar pressures
by Zachary M. Geballe, Nicholas Holtgrewe, Amol Karandikar, Eran Greenberg, Vitali B. Prakapenka, and Alexander F. Goncharov
Author(s): Zachary M. Geballe, Nicholas Holtgrewe, Amol Karandikar, Eran Greenberg, Vitali B. Prakapenka, and Alexander F. Goncharov

The high-pressure melting curves of metals provide simple and useful tests for theories of melting, as well as important constraints for the modeling of planetary interiors. Here, we present an experimental technique that reveals the latent heat of fusion of a metal sample compressed inside a diamon...

[Phys. Rev. Materials 5, 033803] Published Fri Mar 26, 2021
26 Mar 2021 at 11:00am
Effects of light-ion low-fluence implantation on the pressure response of double-walled carbon nanotubes
by G. R. Hearne, L. Kapesi, R. M. Erasmus, S. R. Naidoo, and R. Warmbier
Author(s): G. R. Hearne, L. Kapesi, R. M. Erasmus, S. R. Naidoo, and R. Warmbier

Low-fluence light-ion $(^{11}\mathrm{B}^{+})$ medium-energy (150 keV/ion) implantation preprocessing of double-walled carbon nanotubes (DWCNTs) has been effected to “decorate” them with defects. These are intended to serve as nucleation sites for potential $s{p}^{3}$ interlinking between tube walls ...

[Phys. Rev. Materials 5, 033607] Published Mon Mar 22, 2021
22 Mar 2021 at 11:00am
Pressure-induced structural transition and antiferromagnetism in elemental terbium
by D. P. Kozlenko, V. Yu. Yushankhai, R. Hayn, M. Richter, N. O. Golosova, S. E. Kichanov, E. V. Lukin, and B. N. Savenko
Author(s): D. P. Kozlenko, V. Yu. Yushankhai, R. Hayn, M. Richter, N. O. Golosova, S. E. Kichanov, E. V. Lukin, and B. N. Savenko

Structural and magnetic properties of rare-earth Tb metal have been studied by means of neutron powder diffraction at pressures up to 9 GPa in the temperature range 7–290 K. A structural phase transition from the initial hexagonal close-packed (hcp) to the Sm-type rhombohedral phase develops gradual...

[Phys. Rev. Materials 5, 034402] Published Thu Mar 04, 2021
4 Mar 2021 at 11:00am
Pressure-induced reconstructive phase transition in ${\mathrm{Cd}}_{3}{\mathrm{As}}_{2}$
by Monika Gamża, Paolo Abrami, Lawrence V. D. Gammond, Jake Ayres, Israel Osmond, Takaki Muramatsu, Robert Armstrong, Hugh Perryman, Dominik Daisenberger, Sitikantha Das, and Sven Friedemann
Author(s): Monika Gamża, Paolo Abrami, Lawrence V. D. Gammond, Jake Ayres, Israel Osmond, Takaki Muramatsu, Robert Armstrong, Hugh Perryman, Dominik Daisenberger, Sitikantha Das, and Sven Friedemann

Cadmium arsenide $({\mathrm{Cd}}_{3}{\mathrm{As}}_{2})$ hosts massless Dirac electrons in its ambient-condition tetragonal phase. We report x-ray diffraction and electrical resistivity measurements of ${\mathrm{Cd}}_{3}{\mathrm{As}}_{2}$ upon cycling pressure beyond the critical pressure of the tetr...

[Phys. Rev. Materials 5, 024209] Published Fri Feb 26, 2021
26 Feb 2021 at 11:00am
High-precision equation of state benchmark for cryogenic liquid deuterium at ultrahigh pressure
by Zhiyu He, Qili Zhang, Haifeng Liu, Guo Jia, Xiuguang Huang, Zhiheng Fang, Zhiyong Xie, Junjian Ye, Hua Shu, Jiaqin Dong, Fan Zhang, Yuchun Tu, Wei Wang, and Sizu Fu
Author(s): Zhiyu He, Qili Zhang, Haifeng Liu, Guo Jia, Xiuguang Huang, Zhiheng Fang, Zhiyong Xie, Junjian Ye, Hua Shu, Jiaqin Dong, Fan Zhang, Yuchun Tu, Wei Wang, and Sizu Fu

We provide a principal Hugoniot of cryogenic liquid deuterium at a pressure of $27<P<240$ GPa, with reflected-shock data of up to $∼830$ GPa. The maximum density reaches $∼1.49$ $\mathrm{g}/{\mathrm{cm}}^{3}$, about 8.7 times the initial density. Our independent principal Hugoniot experimental...

[Phys. Rev. B 103, 134107] Published Mon Apr 12, 2021
12 Apr 2021 at 12:00pm
Ab initio lattice thermal conductivity of $\mathrm{Mg}\mathrm{Si}{\mathrm{O}}_{3}$ across the perovskite-postperovskite phase transition
by Zhen Zhang and Renata M. Wentzcovitch
Author(s): Zhen Zhang and Renata M. Wentzcovitch

Lattice thermal conductivity (${κ}_{\mathrm{lat}}$) of $\mathrm{Mg}\mathrm{Si}{\mathrm{O}}_{3}$ postperovskite (MgPPv) under the Earth's lower mantle high pressure-temperature conditions is studied using the phonon quasiparticle approach by combing ab initio molecular dynamics and lattice dynamics s...

[Phys. Rev. B 103, 144103] Published Mon Apr 12, 2021
12 Apr 2021 at 12:00pm
Pressure-induced bcc-rhombohedral phase transition in vanadium metal
by M. G. Stevenson, E. J. Pace, C. V. Storm, S. E. Finnegan, G. Garbarino, C. W. Wilson, D. McGonegle, S. G. Macleod, and M. I. McMahon
Author(s): M. G. Stevenson, E. J. Pace, C. V. Storm, S. E. Finnegan, G. Garbarino, C. W. Wilson, D. McGonegle, S. G. Macleod, and M. I. McMahon

Vanadium is reported to undergo a pressure-induced bcc-rhombohedral phase transition at 30–70 GPa, with a transition pressure that is sensitive to the hydrostaticity of the sample environment. However, the experimental evidence for the structure of the high-pressure phase being rhombohedral is surpr...

[Phys. Rev. B 103, 134103] Published Thu Apr 08, 2021
8 Apr 2021 at 12:00pm
In situ electrical resistivity and viscosity measurements of iron alloys under pressure using synchrotron X-ray radiography
by A. Pommier
Volume 41, Issue 1, March 2021, Page 1-13
.

29 Dec 2020 at 3:18am
The solubility behavior of NaCl in water at high pressure studied by neutron diffraction and Raman scattering
by Qiwei Hu
Volume 41, Issue 1, March 2021, Page 39-51
.

4 Jan 2021 at 10:17am
Structure and vibration spectra of strontium and magnesium oxalates at high pressure
by I.G. Batyrev
Volume 41, Issue 1, March 2021, Page 52-64
.

9 Mar 2021 at 2:11am
High-pressure and high-temperature neutron-diffraction experiments using Kawai-type multi-anvil assemblies
by Asami Sano-Furukawa
Volume 41, Issue 1, March 2021, Page 65-74
.

11 Jan 2021 at 5:30am
Pressure calibration based on the ultrasonic measurement in multi-anvil apparatus
by Wei Song
Volume 41, Issue 1, March 2021, Page 75-87
.

26 Dec 2020 at 10:38am
Clamp cells for high pressure neutron scattering at low temperatures and high magnetic fields at Heinz Maier-Leibnitz Zentrum (MLZ)
by A. Eich
Volume 41, Issue 1, March 2021, Page 88-96
.

12 Nov 2020 at 7:18am
Preparation of SEM hydrogel samples using a high pressure water freeze fracture method
by Hirofumi Satani
Volume 41, Issue 1, March 2021, Page 97-108
.

26 Dec 2020 at 10:35am
Pressure tolerance of brine shrimp (Artemia)
by Ryo Kitahara
Volume 41, Issue 1, March 2021, Page 109-117
.

15 Dec 2020 at 3:54am
Hydrostaticity in high pressure experiments: some general observations and guidelines for high pressure experimenters
by K. Takemura
.

25 Mar 2021 at 6:06am
Using high hydrostatic pressure as an abiotic elicitor strategy for improving capsaicin production in free and immobilized cell suspension cultures of Capsicum annuum L.
by Cemil İşlek
.

25 Mar 2021 at 6:03am