Finite-size scaling study of the liquid-vapour critical point of dipolar square-well fluids

Marianela Martín-Betancourt (1) , Jose Manuel Romero Enrique (1) , Luis F. Rull (1)

1 Departamento de Física Atómica, Molecular y Nuclear

We present Monte Carlo simulation study in the Grand-Canonical ensemble of the liquid-vapour equilibrium of the dipolar square-well fluid for reduced dipolar moments m*≡ m/√(εσ³) in a range between 1 and √7, where ε is the square-well depth and σ the hard-core diameter. We locate the critical points by using the Bruce-Wilding mixed-field finite-size scaling method. In order to get the phase coexistence, we use a multiple-histogram reweighting technique. Our results are consistent with previous estimations reported in the literature, showing that the reduced critical temperature increases in terms of the square-well energy unit as the dipolar moment increases, but decreases if we take as energy unit the nose-to-tail configuration dipolar interaction. On the other hand, the critical density decreases by increasing the dipolar moment. Finally we characterize how the microscopic structure of the coexisting phases depends on the dipolar moment, paying special attention to the clustering and chain formation.

Mots clés: Physical Sciences

Marianela Martín-Betancourt, Jose Manuel Romero Enrique, Luis F. Rull. Finite-size scaling study of the liquid-vapour critical point of dipolar square-well fluids. Molecular Physics, 2009, 107 (04-06), pp.563-570. ⟨10.1080/00268970902889659⟩. ⟨hal-00513285⟩