Publications de Richard Gaal | EPFL Graph Search

Author Correction: Structural phase transition in NH4F under extreme pressure conditions

In the Acknowledgements section the following sentence was added: We acknowledge the European Synchrotron Radiation Facility for provision of synchrotron radiation facilities, and we would like to thank Michael Hanfland and Mohamed Mezouar for assistance i ...

Springer Science and Business Media LLC2025

Hydrogen Hydrates Under Extreme Conditions: Insights Into High-pressure Phases and Implications for Planetary Interiors

Richard Gaal, Livia Eleonora Bove Kado, Tomasz Poreba

Hydrogen hydrates, formed from hydrogen and water under high-pressure and low-temperature conditions, exhibit a rich phase behavior governed by intricate intermolecular interactions. Their structural evolution under extreme conditions provides a unique pla ...

AMER PHYSICAL SOC2025

Observation of plastic ice VII by quasi-elastic neutron scattering

Richard Gaal, Livia Eleonora Bove Kado, Maria Rescigno

Water is the third most abundant molecule in the universe and a key component in the interiors of icy moons, giant planets and Uranus- and Neptune-like exoplanets1, 2–3. Owing to its distinct molecular structure and flexible hydrogen bonds that readily ada ...

2025

Bullet pressure-cell design for neutron scattering experiments with horizontal magnetic fields and dilution temperatures

Henrik Moodysson Rønnow, Richard Gaal, Luc Testa, Ellen Fogh, Gaétan Charles Antoine Giriat, Jana Pásztorová

The simultaneous application of high magnetic fields and high pressures for controlling magnetic ground states is important for testing our understanding of many-body quantum theory. However, the implementation for neutron scattering experiments presents a ...

2025

Cavity-magnon-polariton spectroscopy of strongly hybridized electro-nuclear spin excitations in LiHoF4

Henrik Moodysson Rønnow, Ivica Zivkovic, Richard Gaal, Peter Babkevich

We first present a formalism that incorporates the input-output formalism and the linear response theory to employ cavity-magnon-polariton coupling as a spectroscopic tool for investigating strongly hybridized electro-nuclear spin excitations. A microscopi ...

Nature Research2024

Structural phase transition in NH₄F under extreme pressure conditions

Richard Gaal

Ammonium fluoride (NH₄F) exhibits a variety of crystalline phases depending on temperature and pressure. By employing Raman spectroscopy and synchrotron X-ray diffraction beyond megabar pressures (up to 140 GPa), we have here observed a novel dense solid p ...

2024

Large-cage occupation and quantum dynamics of hydrogen molecules in sII clathrate hydrates

Richard Gaal, Livia Eleonora Bove Kado, Umbertoluca Ranieri

Hydrogen clathrate hydrates are ice-like crystalline substances in which hydrogen molecules are trapped inside polyhedral cages formed by the water molecules. Small cages can host only a single H-2 molecule, while each large cage can be occupied by up to f ...

Aip Publishing2024

Giant Splitting of the Hydrogen Rotational Eigenenergies in the C2 Filled Ice

Richard Gaal

Hydrogen hydrates exhibit a rich phase diagram influenced by both pressure and temperature, with the so-called C2 phase emerging prominently above 2.5 GPa. In this phase, hydrogen molecules are densely packed within a cubic icelike lattice and the interact ...

2024

Pressure dependence of superconducting properties of layered BaNi2P2

Henrik Moodysson Rønnow, Ivica Zivkovic, Richard Gaal, Youngro Lee

The discovery of unconventional superconductivity in a broad class of iron-based materials invoked extensive research on the corresponding compounds of other transition metals. For instance, BaNi2P2 exhibits a superconducting transition with a critical tem ...

Elsevier2023

Observation of the most H2-dense filled ice under high pressure

Richard Gaal, Livia Eleonora Bove Kado, Lorenzo Monacelli, Maria Rescigno

Hydrogen hydrates are among the basic constituents of our solar system's outer planets, some of their moons, as well Neptune-like exo-planets. The details of their high-pressure phases and their thermodynamic conditions of formation and stability are funda ...

National Academy of Sciences2023