Thermal disruption of the inherent structure of simple liquids

Short range order in liquids formally may be viewed as an inherent structure (amorphous particle packings) that has been smeared by thermally induced vibrational distortions. In order to study these distortions, we have employed molecular-dynamics computer simulation, with steepest-descent quenching to potential energy minima, for a model system resembling liquefied noble gases. A typical multidimensional path connecting the liquid configuration to its quench packing is found to be tortuous and characteristic of substantial anharmonicity. In this respect, thermodynamically stable liquids differ qualitatively from crystals and low- temperature amorphous solids. On the basis of evidence from quench path geometry, and by observing how particle pairs redistribute as a result of the quench, an hierarchical domain clustering picture emerges to characterize vibrational anharmonicity in liquids.