van de Bund, Sebastiaan; Ackland, Graeme J.; Wiebe, Heather. (2021). Isotope quantum effects in the metallization transition in liquid hydrogen, [dataset]. University of Edinburgh. School of Physics and Astronomy. https://doi.org/10.7488/ds/3042.
Quantum effects in condensed matter normally only occur at low temperatures. Here we show a large quantum effect in high-pressure liquid hydrogen at thousands of Kelvins. We show that the metallization transition in hydrogen is subject to a very large isotope effect, occurring hundreds of degrees lower than the equivalent transition in deuterium. We examined this using path integral molecular dynamics simulations which identify a liquid-liquid transition involving atomization, metallization, and changes in viscosity, specific heat and compressibility. The difference between H2 and D2 is a quantum mechanical effect which can be associated with the larger zero-point energy in H2 weakening the covalent bond. Our results mean that experimental results on deuterium must be corrected before they are relevant to understanding hydrogen at planetary conditions.
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