### Resumé

potential. The solid phase is face-centered cubic (fcc) at low densities and pressures. At higher densities and pressures, the solid phase is bodycentered cubic (bcc) with a re-entrant liquid phase at the highest pressures simulated. The investigation first identifies the phase diagram at

zero temperature at which the following four crystal structures are considered: fcc, bcc, hexagonal close packed, and cubic diamond. There is a

T = 0 phase transition at pressure 2.651 × 10−3 with the thermodynamically stable structure being fcc below and bcc above this pressure. The

densities of the two crystal structures at the phase transition are 1.7469 × 10−2

(fcc) and 1.7471 × 10−2

(bcc). At finite temperatures, the fcc–

bcc, fcc-liquid, and bcc-liquid coexistence lines are determined by numerical integration of the Clausius–Clapeyron equation and validated

by interface-pinning simulations at selected state points. The bcc-fcc phase transition is a weak first-order transition. The liquid-fcc–bcc triple

point, which is determined by the interface-pinning method, has temperature 5.9 × 10−5

and pressure 2.5 × 10−6

; the triple-point densities

are 1.556 × 10−3

(liquid), 1.583 × 10−3

(bcc), and 1.587 × 10−3

(fcc).

Originalsprog | Engelsk |
---|---|

Artikelnummer | 174501 |

Tidsskrift | Journal of Chemical Physics |

Vol/bind | 2019 |

Udgave nummer | 150 |

Antal sider | 9 |

ISSN | 0021-9606 |

DOI | |

Status | Udgivet - 3 maj 2019 |

### Citer dette

}

**The EXP pair-potential system. III. Thermodynamic phase diagram.** / Pedersen, Ulf Rørbæk; Bacher, Andreas Kvist; Schrøder, Thomas; Dyre, Jeppe.

Publikation: Bidrag til tidsskrift › Tidsskriftartikel › Forskning › peer review

TY - JOUR

T1 - The EXP pair-potential system. III. Thermodynamic phase diagram

AU - Pedersen, Ulf Rørbæk

AU - Bacher, Andreas Kvist

AU - Schrøder, Thomas

AU - Dyre, Jeppe

PY - 2019/5/3

Y1 - 2019/5/3

N2 - This paper determines the thermodynamic phase diagram of the EXP system of particles interacting by the purely repulsive exponential pair potential. The solid phase is face-centered cubic (fcc) at low densities and pressures. At higher densities and pressures, the solid phase is body-centered cubic (bcc) with a re-entrant liquid phase at the highest pressures simulated. The investigation first identifies the phase diagram at zero temperature at which the following four crystal structures are considered: fcc, bcc, hexagonal close packed, and cubic diamond. There is a T = 0 phase transition at pressure 2.651 × 10−3 with the thermodynamically stable structure being fcc below and bcc above this pressure. The densities of the two crystal structures at the phase transition are 1.7469 × 10−2 (fcc) and 1.7471 × 10−2 (bcc). At finite temperatures, the fcc–bcc, fcc-liquid, and bcc-liquid coexistence lines are determined by numerical integration of the Clausius–Clapeyron equation and validated by interface-pinning simulations at selected state points. The bcc-fcc phase transition is a weak first-order transition. The liquid-fcc–bcc triple point, which is determined by the interface-pinning method, has temperature 5.9 × 10−5 and pressure 2.5 × 10−6; the triple-point densities are 1.556 × 10−3 (liquid), 1.583 × 10−3 (bcc), and 1.587 × 10−3 (fcc).

AB - This paper determines the thermodynamic phase diagram of the EXP system of particles interacting by the purely repulsive exponential pair potential. The solid phase is face-centered cubic (fcc) at low densities and pressures. At higher densities and pressures, the solid phase is body-centered cubic (bcc) with a re-entrant liquid phase at the highest pressures simulated. The investigation first identifies the phase diagram at zero temperature at which the following four crystal structures are considered: fcc, bcc, hexagonal close packed, and cubic diamond. There is a T = 0 phase transition at pressure 2.651 × 10−3 with the thermodynamically stable structure being fcc below and bcc above this pressure. The densities of the two crystal structures at the phase transition are 1.7469 × 10−2 (fcc) and 1.7471 × 10−2 (bcc). At finite temperatures, the fcc–bcc, fcc-liquid, and bcc-liquid coexistence lines are determined by numerical integration of the Clausius–Clapeyron equation and validated by interface-pinning simulations at selected state points. The bcc-fcc phase transition is a weak first-order transition. The liquid-fcc–bcc triple point, which is determined by the interface-pinning method, has temperature 5.9 × 10−5 and pressure 2.5 × 10−6; the triple-point densities are 1.556 × 10−3 (liquid), 1.583 × 10−3 (bcc), and 1.587 × 10−3 (fcc).

UR - http://glass.ruc.dk/pdf/articles/2019_JChemPhys_150_174501.pdf

U2 - 10.1063/1.5094395

DO - 10.1063/1.5094395

M3 - Journal article

VL - 2019

JO - Journal of Chemical Physics

JF - Journal of Chemical Physics

SN - 0021-9606

IS - 150

M1 - 174501

ER -