Orientational order in confined dipolar fluids

As a second application of the Ewald summation for systems with slab geometry we now consider strongly coupled confined dipolar liquids, that is, liquids where the dipolar interactions dominate the system s structure and phase behavior. Examples for sucli systems are ferrocolloidal films or confined molecular liquids with strong dipole moments and relatively weak van der Waals forces or hydrogen bonds [231]. 

To this end we performed MC simulations in the mixed isostress isostrain ensemble introduced in Section 5.7 where a thermodynamic state is specified 

This implies that in parallel laboratory experiments the exchange of matter between the confined fluid and a bulk reservoir is insignificant or that a bulk phase in the sense of the SFA experiment (see Section 5.3.1) riiiiy not even be present at all. Such a situation is realized, for example, in the SANS experiments described in Section 4.8.1 where a binary fluid mixture is confined to a nanoporous medium (i.e., pellets) without being in contact with a bulk reservoir. 

The algorithm by which a (numerical representation of a) Markov chain is generated in this ensemble is discussed in detail in Section 5.7.7. However, for the DSS fluid, we need to also include random rotations of the molecules as part of the canonical substep of the algorithm in addition to their random displacement (see Section 5.2.2). 

All simulations were performed for T = 1.35 and m = 3.0. These parameters have already been employed in earlier simulations of bulk DSS fluids for which long-range parallel order at sufficiently high densities or pressures was observed [262-265]. 

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Klapp SHL, Schoen M (2002) Spontaneous orientational order in confined dipolar fluid films. J Chem Phys 117(17) 8050-8062... 

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