Pressure-energy correlations in liquids. I. Results from computer simulations

摘要: We show that a number of model liquids at fixed volume exhibit strong correlations between equilibrium fluctuations the configurational parts (instantaneous) pressure and energy. present detailed results for 13 systems, showing in which systems these are significant. These include Lennard-Jones (both single- two-component) several other simple liquids, neither hydrogen-bonding such as methanol water, nor Dzugutov liquid, has significant contributions to second nearest neighbor distance. The pressure-energy correlations, case shown also be crystal glass phases, reflect an effective inverse power-law potential dominating fluctuations, even zero slightly negative pressure. An exception explanation is liquid with hard-sphere repulsion square-well attractive part, where correlation observed, but only after time averaging. companion paper [N. P. Bailey et al., J. Chem. Phys. 129, 184508 (2008)] gives thorough analysis focus on discussion some experimental theoretical consequences.