EHPRG

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.

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

The Drosophila Trpm channel mediates calcium influx during egg activation [Developmental Biology]
by Qinan Hu, Mariana F. Wolfner
Egg activation is the process in which mature oocytes are released from developmental arrest and gain competency for embryonic development. In Drosophila and other arthropods, eggs are activated by mechanical pressure in the female reproductive tract, whereas in most other species, eggs are activated by fertilization. Despite the difference in...
17 Sep 2019 at 6:01pm
Land-atmosphere feedbacks exacerbate concurrent soil drought and atmospheric aridity [Earth, Atmospheric, and Planetary Sciences]
by Sha Zhou, A. Park Williams, Alexis M. Berg, Benjamin I. Cook, Yao Zhang, Stefan Hagemann, Ruth Lorenz, Sonia I. Seneviratne, Pierre Gentine
Compound extremes such as cooccurring soil drought (low soil moisture) and atmospheric aridity (high vapor pressure deficit) can be disastrous for natural and societal systems. Soil drought and atmospheric aridity are 2 main physiological stressors driving widespread vegetation mortality and reduced terrestrial carbon uptake. Here, we empirically demonstrate that strong...
17 Sep 2019 at 6:01pm
Ultraslow radiative cooling of [math] (n = 3–5)
by James N. Bull
The Journal of Chemical Physics, Volume 151, Issue 11, September 2019.
Ultraslow radiative cooling lifetimes and adiabatic detachment energies for three astrochemically relevant anions, [math] (n = 3–5), are measured using the Double ElectroStatic Ion Ring ExpEriment (DESIREE) infrastructure at Stockholm University. DESIREE maintains a background pressure of ≈10−14 mbar and temperature of ≈13 K, allowing storage of mass-selected ions for hours and providing conditions coined a “molecular cloud in a box.” Here, we construct two-dimensional (2D) photodetachment spectra for the target anions by recording photodetachment signal as a function of irradiation wavelength and ion storage time (seconds to minute time scale). Ion cooling lifetimes, which are associated with infrared radiative emission, are extracted from the 2D photodetachment spectrum for each ion by tracking the disappearance of vibrational hot-band signal with ion storage time, giving [math] cooling lifetimes of 3.1 ± 0.1 s ([math]), 6.8 ± 0.5 s ([math]), and 24 ± 5 s ([math]). Fits of the photodetachment spectra for cold ions, i.e., those stored for at least 30 s, provide adiabatic detachment energies in good agreement with values from laser photoelectron spectroscopy on jet-cooled anions, confirming that radiative cooling has occurred in DESIREE. Ion cooling lifetimes are simulated using a simple harmonic cascade model, finding good agreement with experiment and providing a mode-by-mode understanding of the radiative cooling properties. The 2D photodetachment strategy and radiative cooling modeling developed in this study could be applied to investigate the ultraslow cooling dynamics of a wide range of molecular anions.
17 Sep 2019 at 5:15am
On the role of intermolecular vibrational motions for ice polymorphs I: Volumetric properties of crystalline and amorphous ices
by Hideki Tanaka
The Journal of Chemical Physics, Volume 151, Issue 11, September 2019.
Intermolecular vibrations and volumetric properties are investigated using the quasiharmonic approximation with the TIP4P/2005, TIP4P/Ice, and SPC/E potential models for most of the known crystalline and amorphous ice forms that have hydrogen-disordering. The ice forms examined here cover low pressure ices (hexagonal and cubic ice I, XVI, and hypothetical dtc ice), medium pressure ices (III, IV, V, VI, XII, hydrogen-disordered variant of ice II), and high pressure ice (VII) as well as the low density and the high density amorphous forms. We focus on the thermal expansivities and the isothermal compressibilities in the low temperature regime over a wide range of pressures calculated via the intermolecular vibrational free energies. Negative thermal expansivity appears only in the low pressure ice forms. The sign of the thermal expansivity is elucidated in terms of the mode Grüneisen parameters of the low frequency intermolecular vibrational motions. Although the band structure for the low frequency region of the vibrational density of state in the medium pressure ice has a close resemblance to that in the low pressure ice, its response against volume variation is opposite. We reveal that the mixing of translational and rotational motions in the low frequency modes plays a crucial role in the appearance of the negative thermal expansivity in the low pressure ice forms. The medium pressure ices can be further divided into two groups in terms of the hydrogen-bond network flexibility, which is manifested in the properties on the molecular rearrangement against volume variation, notably the isothermal compressibility.
18 Sep 2019 at 7:47am
Can clathrates heterogeneously nucleate ice?
by Matías H. Factorovich
The Journal of Chemical Physics, Volume 151, Issue 11, September 2019.
Methane hydrates can be preserved at ambient pressure, beyond their region of thermodynamic stability, by storing them at temperatures from 240 to 270 K. The origin of this anomalous self-preservation is the formation of an ice coating that covers the clathrate particles and prevents further loss of gas. While there have been several studies on self-preservation, the question of what is the mechanism by which ice nucleates on the decomposing clathrate hydrates has not yet been fully explained. Here, we use molecular simulations, thermodynamic analysis, and nucleation theory to investigate possible scenarios for the nucleation of ice: heterogeneous nucleation at the clathrate/vapor or clathrate/liquid interfaces and homogeneous nucleation from supercooled water. Our results indicate that clathrates cannot heterogeneously nucleate ice and that ice nucleation is due to the cooling of water at the decomposing clathrate/liquid interface, which suffices to trigger homogeneous ice nucleation. We find that the (111) face of the sII structure clathrate can bind to the (111) plane of cubic ice or the basal plane of hexagonal ice through domain matching, resulting in a weak binding that—while insufficient to promote heterogeneous ice nucleation—suffices to produce epitaxy and alignment between these crystals. We use thermodynamic relations, theory, and the contact angles of ice at the (111) sII clathrate/liquid interface to determine—for the first time—the interfacial free energy of this most favorable ice-clathrate interface, 59 ± 5 mJ/m2. We discuss the implications of our results for the feasibility of heterogeneous nucleation of gas clathrates at ice/vapor interfaces.
20 Sep 2019 at 3:31am
Solvation effect on binding modes of model lignin dimer compounds on MWW 2D-zeolite
by Varsha Jain
The Journal of Chemical Physics, Volume 151, Issue 11, September 2019.
Lignin as a potential renewable source of biofuels, chemicals, and other value-added products has gained much attention. However, the complexity of lignin structure poses a significant challenge for developing efficient valorization techniques. As most processes involve solvothermal conditions to minimize energy cost, lignin depolymerization is governed by reaction conditions (temperature and pressure) and solvents. In this work, binding of β–O–4 linkage consisting lignin dimers on MWW two-dimensional (2D) zeolite is investigated using periodic density functional theory. Furthermore, the effect of different terminated surfaces (H:OH% = 100:0; 50:50; 0:100%), different temperatures (323, 353, 373 K), and different solvents (water and methanol) on the binding modes is quantified. Our work shows that in the gas phase the binding strength increases 10–15 kcal/mol upon increasing the number of hydroxyl groups on the surface. Also, the phenolic dimer binds more strongly than the nonphenolic dimer, and the binding strength of model compounds increases in the presence of the solvent. Analysis of structural changes in the presence of the solvent reveals that the aromatic rings are parallel to the zeolite surface and primary interaction with zeolite is through the hydroxyl groups near the β–O–4 linkage. Furthermore, while the solvation energy decreases with increasing temperature, the opposite trend is observed for the binding energy with the surface.
20 Sep 2019 at 3:34am
Experimental Evidence for a State-Point-Independent Density-Scaling Exponent in Ionic Liquids
by Z. Wojnarowska, M. Musiał, M. Dzida, and M. Paluch
Author(s): Z. Wojnarowska, M. Musiał, M. Dzida, and M. Paluch


This Letter addresses a fundamental issue of condensed-matter physics, which is the validity of the density-scaling concept. For this purpose, the ambient and high-pressure conductivity measurements of two selected ionic liquids (ILs), with the different contribution of H-bonding interactions, were ...


[Phys. Rev. Lett. 123, 125702] Published Wed Sep 18, 2019
18 Sep 2019 at 12:00pm
Formation of a High Pressure Staircase Pedestal with Suppressed Edge Localized Modes in the DIII-D Tokamak
by Arash Ashourvan, R. Nazikian, E. Belli, J. Candy, D. Eldon, B. A. Grierson, W. Guttenfelder, S. R. Haskey, C. Lasnier, G. R. McKee, and C. C. Petty
Author(s): Arash Ashourvan, R. Nazikian, E. Belli, J. Candy, D. Eldon, B. A. Grierson, W. Guttenfelder, S. R. Haskey, C. Lasnier, G. R. McKee, and C. C. Petty


We observe the formation of a high-pressure staircase pedestal ($≈16–20\text{ }\text{ }\mathrm{kPa}$) in the DIII-D tokamak when large amplitude edge localized modes are suppressed using resonant magnetic perturbations. The staircase pedestal is characterized by a flattening of the density and tempe...


[Phys. Rev. Lett. 123, 115001] Published Thu Sep 12, 2019
12 Sep 2019 at 12:00pm
Pressure-Induced Hydrogen-Hydrogen Interaction in Metallic FeH Revealed by NMR
by Thomas Meier, Florian Trybel, Saiana Khandarkhaeva, Gerd Steinle-Neumann, Stella Chariton, Timofey Fedotenko, Sylvain Petitgirard, Michael Hanfland, Konstantin Glazyrin, Natalia Dubrovinskaia, and Leonid Dubrovinsky
Author(s): Thomas Meier, Florian Trybel, Saiana Khandarkhaeva, Gerd Steinle-Neumann, Stella Chariton, Timofey Fedotenko, Sylvain Petitgirard, Michael Hanfland, Konstantin Glazyrin, Natalia Dubrovinskaia, and Leonid Dubrovinsky


Nuclear magnetic resonance experiments reveal how the electronic properties of hydrogen in iron hydride change under extreme pressure, a step toward understanding the onset of high-temperature superconductivity in metal hydrides.


[Phys. Rev. X 9, 031008] Published Wed Jul 17, 2019
17 Jul 2019 at 12:00pm
Solids, liquids, and gases under high pressure
by Ho-Kwang Mao, Xiao-Jia Chen, Yang Ding, Bing Li, and Lin Wang
Author(s): Ho-Kwang Mao, Xiao-Jia Chen, Yang Ding, Bing Li, and Lin Wang


The effect of adding high pressure as a control parameter in solids, liquids, and gases expands opportunities to observe unexpected novel phenomena and understand matter in extreme environments. This review on high pressure science highlights subjects ranging from quantum criticality to Earth science. State-of-the-art experimental methods at megabar pressures are also discussed. The proliferation of pressure-induced phases illustrate promising new directions for this field of research.


[Rev. Mod. Phys. 90, 015007] Published Tue Mar 20, 2018
20 Mar 2018 at 11:00am
Colloquium: High pressure and road to room temperature superconductivity
by Lev P. Gor’kov and Vladimir Z. Kresin
Author(s): Lev P. Gor’kov and Vladimir Z. Kresin


Even after three decades of development, high-temperature superconductivity remains one of the most challenging theoretical and experimental areas in condensed matter physics. In this Colloquium some new discoveries in this area are reviewed and possible routes toward much higher transition temperatures are analyzed.


[Rev. Mod. Phys. 90, 011001] Published Tue Jan 09, 2018
9 Jan 2018 at 11:00am
Theoretical assessment of the structure and stability of the $λ$ phase of nitrogen
by Watit Sontising and Gregory J. O. Beran
Author(s): Watit Sontising and Gregory J. O. Beran


The $λ$ phase of nitrogen was reported in 2016 and is one of more than a dozen high-pressure solid nitrogen forms that have been discovered. However, its crystal structure could not be solved unambiguously from powder diffraction alone; rather the reported structure was determined by combining exper...


[Phys. Rev. Materials 3, 095002] Published Fri Sep 13, 2019
13 Sep 2019 at 12:00pm
Evidence for pressure-induced polarization rotation, octahedral tilting, and reentrant ferroelectric phase in tetragonal $(\mathrm{P}{\mathrm{b}}_{0.5}\mathrm{B}{\mathrm{i}}_{0.5})(\mathrm{T}{\mathrm{i}}_{0.5}\mathrm{F}{\mathrm{e}}_{0.5}){\mathrm{O}}_{3}$
by Pragya Singh, Chandan Upadhyay, Zuzana Konôpková, Hanns-Peter Liermann, and Dhananjai Pandey
Author(s): Pragya Singh, Chandan Upadhyay, Zuzana Konôpková, Hanns-Peter Liermann, and Dhananjai Pandey


Pressure-induced phase transition in the technologically important tetragonal phase of ${\mathrm{PbTiO}}_{3}$ has been quite controversial with two entirely different propositions: (1) morphotropic phase boundary-like structural transition with concomitant rotation of the ferroelectric polarization ...


[Phys. Rev. Materials 3, 094405] Published Wed Sep 11, 2019
11 Sep 2019 at 12:00pm
Suppression of the antiferromagnetic metallic state in the pressurized $\mathrm{MnB}{\mathrm{i}}_{2}\mathrm{T}{\mathrm{e}}_{4}$ single crystal
by K. Y. Chen, B. S. Wang, J.-Q. Yan, D. S. Parker, J.-S. Zhou, Y. Uwatoko, and J.-G. Cheng
Author(s): K. Y. Chen, B. S. Wang, J.-Q. Yan, D. S. Parker, J.-S. Zhou, Y. Uwatoko, and J.-G. Cheng


We study the effect of hydrostatic pressure on the electrical transport, magnetic, and structural properties of $\mathrm{MnB}{\mathrm{i}}_{2}\mathrm{T}{\mathrm{e}}_{4}$ by measuring its resistivity, Hall effect, and x-ray diffraction under pressures up to 12.8 GPa supplemented by the first-principle...


[Phys. Rev. Materials 3, 094201] Published Tue Sep 03, 2019
3 Sep 2019 at 12:00pm
Formation of graphene atop a Si adlayer on the C-face of SiC
by Jun Li, Qingxiao Wang, Guowei He, Michael Widom, Lydia Nemec, Volker Blum, Moon Kim, Patrick Rinke, and Randall M. Feenstra
Author(s): Jun Li, Qingxiao Wang, Guowei He, Michael Widom, Lydia Nemec, Volker Blum, Moon Kim, Patrick Rinke, and Randall M. Feenstra


The structure of the SiC($000\overline{1}$) surface, the C-face of the {0001} SiC surfaces, is studied as a function of temperature and of pressure in a gaseous environment of disilane ($\mathrm{S}{\mathrm{i}}_{2}{\mathrm{H}}_{6}$). Various surface reconstructions are observed, both with and without...


[Phys. Rev. Materials 3, 084006] Published Mon Aug 19, 2019
19 Aug 2019 at 12:00pm
Atomic-scale coexistence of short-range magnetic order and superconductivity in ${\mathrm{Fe}}_{1+y}{\mathrm{Se}}_{0.1}{\mathrm{Te}}_{0.9}$
by Ramakrishna Aluru, Haibiao Zhou, Antoine Essig, J.-Ph. Reid, Vladimir Tsurkan, Alois Loidl, Joachim Deisenhofer, and Peter Wahl
Author(s): Ramakrishna Aluru, Haibiao Zhou, Antoine Essig, J.-Ph. Reid, Vladimir Tsurkan, Alois Loidl, Joachim Deisenhofer, and Peter Wahl


The ground state of the parent compounds of many high-temperature superconductors is an antiferromagnetically ordered phase, where superconductivity emerges when the antiferromagnetic phase transition is suppressed by doping or application of pressure. This behavior implies a close relation between ...


[Phys. Rev. Materials 3, 084805] Published Mon Aug 19, 2019
19 Aug 2019 at 12:00pm
Pressure-induced superconductivity in $\mathrm{B}{\mathrm{i}}_{2−x}\mathrm{S}{\mathrm{b}}_{x}\mathrm{T}{\mathrm{e}}_{3−y}\mathrm{S}{\mathrm{e}}_{y}$
by Tong He, Xiaofan Yang, Tomoya Taguchi, Teppei Ueno, Kaya Kobayashi, Jun Akimitsu, Hitoshi Yamaoka, Hirofumi Ishii, Yen-Fa Liao, Hiromi Ota, Hidenori Goto, Ritsuko Eguchi, Kensei Terashima, Takayoshi Yokoya, Harald O. Jeschke, Xianxin Wu, and Yoshihiro Kubozono
Author(s): Tong He, Xiaofan Yang, Tomoya Taguchi, Teppei Ueno, Kaya Kobayashi, Jun Akimitsu, Hitoshi Yamaoka, Hirofumi Ishii, Yen-Fa Liao, Hiromi Ota, Hidenori Goto, Ritsuko Eguchi, Kensei Terashima, Takayoshi Yokoya, Harald O. Jeschke, Xianxin Wu, and Yoshihiro Kubozono


We systematically investigated the pressure dependence of electrical transport and the crystal structure of topological insulator, $\mathrm{B}{\mathrm{i}}_{2−x}\mathrm{S}{\mathrm{b}}_{x}\mathrm{T}{\mathrm{e}}_{3−y}\mathrm{S}{\mathrm{e}}_{y}$, which showed no superconductivity down to 2.0 K at ambien...


[Phys. Rev. B 100, 094525] Published Thu Sep 19, 2019
19 Sep 2019 at 12:00pm
Superconductivity with strong electron-phonon coupling in noncentrosymmetric ${\mathrm{W}}_{3}{\mathrm{Al}}_{2}\mathrm{C}$
by T. P. Ying, Y. P. Qi, and H. Hosono
Author(s): T. P. Ying, Y. P. Qi, and H. Hosono


We report the discovery of superconductivity in ${\mathrm{W}}_{3}{\mathrm{Al}}_{2}\mathrm{C}$ (${T}_{c}=7.6\phantom{\rule{0.16em}{0ex}}\mathrm{K}$) synthesized by high-pressure method. ${\mathrm{W}}_{3}{\mathrm{Al}}_{2}\mathrm{C}$ is isostructural to ${\mathrm{Mo}}_{3}{\mathrm{Al}}_{2}\mathrm{C}$ (s...


[Phys. Rev. B 100, 094522] Published Wed Sep 18, 2019
18 Sep 2019 at 12:00pm
Development of a technique for high pressure neutron diffraction at 40 GPa with a Paris-Edinburgh press
by T. Hattori
Volume 39, Issue 3, September 2019, Page 417-425
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4 Jun 2019 at 6:21am
Modified Bridgman anvils for high pressure synthesis and neutron scattering
by Bianca Haberl
Volume 39, Issue 3, September 2019, Page 426-437
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17 Jun 2019 at 8:18am
Ultrahigh pressure equation of state of tantalum to 310 GPa
by Kaleb C. Burrage
Volume 39, Issue 3, September 2019, Page 489-498
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11 Jul 2019 at 8:28am
In-situ X-ray diffraction study on β-CrOOH at high pressure and high-temperature
by Chikara Shito
Volume 39, Issue 3, September 2019, Page 499-508
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17 Jul 2019 at 2:46pm
Effects of high hydrostatic pressure on β-glucan content, swelling power, starch damage, and pasting properties of high-β-glucan barley flour
by Shigeaki Ueno
Volume 39, Issue 3, September 2019, Page 509-524
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29 Mar 2019 at 1:58pm
The usage of high hydrostatic pressure (HHP) to control food-borne pathogens in hummus
by Barbara Sokołowska
Volume 39, Issue 3, September 2019, Page 525-532
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24 Jun 2019 at 12:09pm
Hydrostaticity of pressure-transmitting media for high pressure infrared spectroscopy
by A. Celeste
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20 Sep 2019 at 11:59am
Enhancing the pressure limitation in large-volume Bridgman-anvil cell used for in situ neutron diffraction
by Qiwei Hu
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19 Sep 2019 at 1:28pm
High hydrostatic pressure processing of beetroot juice: effects on nutritional, sensory and microbiological quality
by Marta Ubeira-Iglesias
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19 Sep 2019 at 1:24pm
Lattice distortion-induced sluggish phase transition in CoCrFeNixAl1-x (x = 0.5, 0.75) high-entropy alloys at high pressures
by Lei Liu
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16 Aug 2019 at 12:07pm