Ab initio simulation of particle momentum distributions in high-pressure water

6th Workshop in Electron Volt Neutron Spectroscopy: Frontiers and Horizons

Ceriotti, M.^1

Laboratory of Computational Science and Modelling, NQ Institute of Materials, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne

CH-1015, Switzerland^1

关键词: Ab initio simulations;    Applying pressure;    Deep inelastic scattering;    Extreme pressure;    High-pressure water;    Hydrogen nuclei;    Particle momentum;    Path-integral molecular dynamics;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/571/1/012011/pdf
DOI  :  10.1088/1742-6596/571/1/012011

来源: IOP

【 摘 要 】

Applying pressure to water reduces the average oxygen-oxygen distance, and facilitates the delocalisation of protons along the hydrogen bond. This pressure-induced delocalisation is further enhanced by the quantum nature of hydrogen nuclei, which is very significant even well above room temperature. Here we will evaluate the quantum kinetic energy and the particle momentum distribution of hydrogen and oxygen nuclei in water at extreme pressure, using ab initio path integral molecular dynamics. We will show that (transient) dissociation of water molecules induce measurable changes in the kinetic energy hydrogen atoms, although current deep inelastic scattering experiments are probably unable to capture the heterogeneity of the sample.