Berlin 2015 – wissenschaftliches Programm

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DY: Fachverband Dynamik und Statistische Physik

DY 51: Complex Fluids and Soft Matter - Part III (joint session DY/ CPP / BP)

DY 51.6: Vortrag

Donnerstag, 19. März 2015, 16:30–16:45, BH-N 334

Dynamical Crossover at the Liquid-Liquid Transformation of a Compressed Molten Alkali Metal — Taras Bryk^1,2, Simone De Panfilis^3,1, Federico A Gorelli^4,5, Eugene Gregoryanz⁶, Michael Krisch⁷, Giancarlo Ruocco^1,5, Mario Santoro⁸, Tullio Scopigno^1,5, and •Ari Paavo Seitsonen^9,10 — ¹Dip. Fisica, Univ. La Sapienza, Roma, Italy — ²Inst. Cond. Matter Phys. of NASU, Lviv, Ukraine — ³Centre for Life Nano Science IIT@Sapienza, Istituto Italiano di Tecnologia, Roma, Italy — ⁴Eur. Lab. for Non-Linear Spectr., Firenze, Italy — ⁵IPCF-CNR, c/o Univ. La Sapienza, Italy — ⁶Centre for Science at Extreme Conditions, Univ. Edinburgh, United Kingdom — ⁷Eur. Synchr. Res. Facility, Grenoble, France — ⁸IFAC-CNR, Sesto Fiorentino, Italy — ⁹Dept. Chemie, Univ. Zürich, Switzerland — ¹⁰Dépt. Chimie, ENS Paris, France

Density-driven phase transformations are a known phenomenon in liquids. Pressure-driven transitions from an open low-density to a higher-density close-packed structure were observed for a number of systems. Here, we show a less intuitive, inverse behavior. We investigated the electronic, atomic, and dynamic structures of liquid Rb along an isothermal line at 573 K, at 1.2-27.4 GPa, by means of ab initio molecular dynamics simulations and inelastic x-ray scattering experiments. Above 12.5 GPa, the breakdown of the nearly-free-electron model drives a transition of the pure liquid metal towards a less metallic, denser liquid, whose first coordination shell is less compact. Our study unveils the interplay between electronic, structural, and dynamic degrees of freedom along this liquid-liquid phase transition.