## 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 EHPRG Meeting

The Joint 28th AIRAPT and 60th EHPRG International Conference on High Pressure Science and Technology (AIRAPT-2023), originally scheduled for July 2021, will be held in Edinburgh, UK, from July 23-28, 2023.
The Conference will be held at the Edinburgh International Conference Centre (EICC) and it will be a face-to-face conference only.
Immediately prior to AIRAPT/EHPRG, from the 19th to 23rd of July 2023, a Summer School will take place, also based in Edinburgh, with accommodation provided in University Halls of Residence. The School is aimed at young researchers, and experimentalists wanting a grounding in theory and vice versa.
For more information, please visit the official webpage of AIRAPT-23.

The 59th European High Pressure Research Group Meeting on High Pressure Science and Technology (EHPRG2022) took place in Uppsala, Sweden, from 5th to 8th September 2022.
Meeting sessions were held virtually. The 59th EHPRG intended to be a large scope conference, in line with the rapid increase of high pressure activities in all areas of Physics, Chemistry, Food Science, Geosciences, Material Research, and Biosciences.
For more information, please visit the official webpage of the 59th EHPRG Meeting.

## High-pressure in the headlines

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

Academia’s culture of overwork almost broke me, so I’m working to undo it
by Natalia Ingebretsen Kucirkova

Nature, Published online: 31 January 2023; doi:10.1038/d41586-023-00241-8

For young immigrant women like me, the pressures of early career research are even greater than for most. But it doesn’t have to be that way.
31 Jan 2023 at 12:00am
A perspective on the microscopic pressure (stress) tensor: History, current understanding, and future challenges
by Kaihang Shi
The Journal of Chemical Physics, Volume 158, Issue 4, January 2023.
The pressure tensor (equivalent to the negative stress tensor) at both microscopic and macroscopic levels is fundamental to many aspects of engineering and science, including fluid dynamics, solid mechanics, biophysics, and thermodynamics. In this Perspective, we review methods to calculate the microscopic pressure tensor. Connections between different pressure forms for equilibrium and nonequilibrium systems are established. We also point out several challenges in the field, including the historical controversies over the definition of the microscopic pressure tensor; the difficulties with many-body and long-range potentials; the insufficiency of software and computational tools; and the lack of experimental routes to probe the pressure tensor at the nanoscale. Possible future directions are suggested.
30 Jan 2023 at 12:48pm
Physical mechanisms of the Soret effect in binary Lennard-Jones liquids elucidated with thermal-response calculations
by Patrick K. Schelling
The Journal of Chemical Physics, Volume 158, Issue 4, January 2023.
The Soret effect is the tendency of fluid mixtures to exhibit concentration gradients in the presence of a temperature gradient. Using molecular-dynamics simulation of two-component Lennard-Jones liquids, it is demonstrated that spatially sinusoidal heat pulses generate both temperature and pressure gradients. Over short timescales, the dominant effect is the generation of compressional waves, which dissipate over time as the system approaches mechanical equilibrium. The approach to mechanical equilibrium is also characterized by a decrease in particle density in the high-temperature region and an increase in particle density in the low-temperature region. It is demonstrated that concentration gradients develop rapidly during the propagation of compressional waves through the liquid. Over longer timescales, heat conduction occurs to return the system to thermal equilibrium, with the particle current acting to restore a more uniform particle density. It is shown that the Soret effect arises due to the fact that the two components of the fluid exhibit different responses to pressure gradients. First, the so-called isotope effect occurs because light atoms tend to respond more rapidly to evolving conditions. In this case, there appears to be a connection to previous observations of “fast sound” in binary fluids. Second, it is shown that the partial pressures of the two components in equilibrium, and more directly, the relative magnitudes of their derivatives with respect to temperature and density, determine which species accumulate in the high- and low-temperature regions. In the conditions simulated here, the dependence of the partial pressure on density gradients is larger than the dependence on temperature gradients. This is directly connected to the accumulation of the species with the largest partial pressure in the high-temperature region and the accumulation of the species with the smallest partial pressure in the low-temperature region. The results suggest that further development of theoretical descriptions of the Soret effect might begin with hydrodynamical equations in two-component liquids. Finally, it is suggested that the recently proposed concept of “thermophobicity” may be related to the sensitivity of partial pressures in a multicomponent fluid to changes in temperature and density.
23 Jan 2023 at 11:55am
Cell-Matrix Elastocapillary Interactions Drive Pressure-Based Wetting of Cell Aggregates
by Muhammad Sulaiman Yousafzai, Vikrant Yadav, Sorosh Amiri, Michael F. Staddon, Youssef Errami, Gwilherm Jaspard, Shiladitya Banerjee, and Michael Murrell
Author(s): Muhammad Sulaiman Yousafzai, Vikrant Yadav, Sorosh Amiri, Michael F. Staddon, Youssef Errami, Gwilherm Jaspard, Shiladitya Banerjee, and Michael Murrell

Observations of pressure-driven motion of cells reveal a novel type of cell migration and cooperation between cellular- and tissue-level forces that may point to unexplored modes of cancer cell movement and early organism development.

[Phys. Rev. X 12, 031027] Published Wed Aug 17, 2022
17 Aug 2022 at 12:00pm
Crystal structures, frustrated magnetism, and chemical pressure in Sr-doped ${\mathrm{Ba}}_{3}\mathrm{Ni}{\mathrm{Sb}}_{2}{\mathrm{O}}_{9}$ perovskites
by Mélanie Viaud, Catherine Guillot-Deudon, Eric Gautron, Maria Teresa Caldes, Guido Berlanda, Philippe Deniard, Philippe Boullay, Florence Porcher, Carole La, Céline Darie, A. Zorko, A. Ozarowski, Fabrice Bert, Philippe Mendels, and Christophe Payen
Author(s): Mélanie Viaud, Catherine Guillot-Deudon, Eric Gautron, Maria Teresa Caldes, Guido Berlanda, Philippe Deniard, Philippe Boullay, Florence Porcher, Carole La, Céline Darie, A. Zorko, A. Ozarowski, Fabrice Bert, Philippe Mendels, and Christophe Payen

The effects of chemical pressure on the structural and magnetic properties of the triple perovskite ${\mathrm{Ba}}_{3}\mathrm{Ni}{\mathrm{Sb}}_{2}{\mathrm{O}}_{9}$ are investigated by substituting ${\mathrm{Sr}}^{2+}$ ions for ${\mathrm{Ba}}^{2+}$ ions. Two ${\mathrm{Ba}}_{3−x}{\mathrm{Sr}}_{x}\math… [Phys. Rev. Materials 6, 124408] Published Tue Dec 20, 2022 20 Dec 2022 at 11:00am Pressure-induced metallization and superconductivity in the layered van der Waals semiconductor GaTe by Jin Jiang, Xuliang Chen (陈绪亮), Shuyang Wang, Chao An, Ying Zhou, Min Zhang, Yonghui Zhou, and Zhaorong Yang Author(s): Jin Jiang, Xuliang Chen (陈绪亮), Shuyang Wang, Chao An, Ying Zhou, Min Zhang, Yonghui Zhou, and Zhaorong Yang Investigations show that the physical properties of the layered van der Waals semiconductor GaTe are strongly layer dependent. Here, the authors systematically study its properties by using external pressure as a tuning knob. They first find pressure-induced metallization and superconductivity simultaneously occurring at ~3 GPa, presumably owing to a quasi-two-dimensional to three-dimensional structural crossover and to an electronic phase transition due to a change of the bonding nature between layers from weak van der Waals interaction to strong Coulomb coupling. A second distinct superconducting phase is then observed at ~10 GPa due to a structural transition. [Phys. Rev. B 107, 024512] Published Tue Jan 31, 2023 31 Jan 2023 at 11:00am$GW+\mathrm{EDMFT}$investigation of${\mathrm{Pr}}_{1−x}{\mathrm{Sr}}_{x}{\mathrm{NiO}}_{2}$under pressure by Viktor Christiansson, Francesco Petocchi, and Philipp Werner Author(s): Viktor Christiansson, Francesco Petocchi, and Philipp Werner Motivated by the recent experimental observation of a large pressure effect on${T}_{c}$in${\mathrm{Pr}}_{1−x}{\mathrm{Sr}}_{x}{\mathrm{NiO}}_{2}$, we study the electronic properties of this compound as a function of pressure for$x=0$and 0.2 doping using self-consistent$GW+\mathrm{EDMFT}$. Our … [Phys. Rev. B 107, 045144] Published Mon Jan 30, 2023 30 Jan 2023 at 11:00am Ramp compression of tantalum to multiterapascal pressures: Constraints of the thermal equation of state to 2.3 TPa and 5000 K by M. G. Gorman, C. J. Wu, R. F. Smith, L. X. Benedict, C. J. Prisbrey, W. Schill, S. A. Bonev, Z. C. Long, P. Söderlind, D. Braun, D. C. Swift, R. Briggs, T. J. Volz, E. F. O'Bannon, P. M. Celliers, D. E. Fratanduono, J. H. Eggert, S. J. Ali, and J. M. McNaney Author(s): M. G. Gorman, C. J. Wu, R. F. Smith, L. X. Benedict, C. J. Prisbrey, W. Schill, S. A. Bonev, Z. C. Long, P. Söderlind, D. Braun, D. C. Swift, R. Briggs, T. J. Volz, E. F. O'Bannon, P. M. Celliers, D. E. Fratanduono, J. H. Eggert, S. J. Ali, and J. M. McNaney The authors use intense laser pulses to compress solid tantalum to pressures in excess of 20 million atmospheres. By combing their experimental measurements with existing high-pressure, high-temperature data on Ta, they can create an experimentally bounded high-temperature equation of state that is valid up to multiterapascal pressures and thousands of degrees kelvin. The equation of state may serve as a useful pressure standard at the extreme compressions and elevated temperatures now achievable in state-of-the-art static compression experiments. This work also provides a clear road map for building an accurate high-temperature equation of state catalogue of materials at extreme conditions. [Phys. Rev. B 107, 014109] Published Fri Jan 27, 2023 27 Jan 2023 at 11:00am Pressure suppression of the excitonic insulator state in${\mathrm{Ta}}_{2}{\mathrm{NiSe}}_{5}$observed by optical conductivity by H. Okamura, T. Mizokawa, K. Miki, Y. Matsui, N. Noguchi, N. Katayama, H. Sawa, M. Nohara, Y. Lu, H. Takagi, Y. Ikemoto, and T. Moriwaki Author(s): H. Okamura, T. Mizokawa, K. Miki, Y. Matsui, N. Noguchi, N. Katayama, H. Sawa, M. Nohara, Y. Lu, H. Takagi, Y. Ikemoto, and T. Moriwaki The layered chalcogenide${\mathrm{Ta}}_{2}{\mathrm{NiSe}}_{5}$has recently attracted much interest as a strong candidate for a long-sought excitonic insulator (EI). Since the physical properties of an EI are expected to depend sensitively on the external pressure ($P$), it is important to clarify … [Phys. Rev. B 107, 045141] Published Fri Jan 27, 2023 27 Jan 2023 at 11:00am Stability of the Pb divalent state in insulating and metallic$\mathrm{PbCr}{\mathrm{O}}_{3}\$
by Jianfa Zhao, Shu-Chih Haw, Xiao Wang, Lipeng Cao, Hong-Ji Lin, Chien-Te Chen, Christoph J. Sahle, Arata Tanaka, Jin-Ming Chen, Changqing Jin, Zhiwei Hu, and Liu Hao Tjeng
Author(s): Jianfa Zhao, Shu-Chih Haw, Xiao Wang, Lipeng Cao, Hong-Ji Lin, Chien-Te Chen, Christoph J. Sahle, Arata Tanaka, Jin-Ming Chen, Changqing Jin, Zhiwei Hu, and Liu Hao Tjeng

PbCrO3 is a perovskite that undergoes a large volume collapse and concurrently an insulator-metal transition with pressure. While one may think that the volume collapse can be associated with conversion of Pb2+ ions to the smaller Pb4+, the spectroscopic measurements in this experiment reveal that the Pb ions remain divalent. Instead, the Cr ions undergo a transition from a charge-disproportionated 2Cr3+/Cr6+ configuration to a homogenous Cr4+ with pressure. Thus, the authors can explain the insulating/metallic nature of PbCrO3 at low/high pressures, respectively.

[Phys. Rev. B 107, 024107] Published Thu Jan 26, 2023
26 Jan 2023 at 11:00am
Investigation of null-matrix alloy gaskets for a diamond-anvil-cell on high pressure neutron diffraction experiments
by Shinichi Machida
Volume 42, Issue 4, December 2022, Page 303-317
.

11 Nov 2022 at 6:06am
Sound velocity anomalies of limestone at high pressure and implications for the mantle wedge
by Fengxia Sun
Volume 42, Issue 4, December 2022, Page 336-348
.

12 Nov 2022 at 1:16pm
Development of an explicit pressure explicit saturation (EPES) method for modelling dissociation processes of methane hydrate
by Giovanni Luzi
.

27 Dec 2022 at 4:10am