Camel back shaped Kirkwood-Buff Integrals

Abstract

Some binary mixtures, such as specific alcohol-alkane mixtures, or even water-tbutanol, exhibit two humps camel back shaped KBI. This is in sharp contrast with usual KBI of binary mixtures having a single extremum. This extremum is interpreted as the region of maximum concentration fluctuations, and usually occurs in binary mixtures presenting appreciable micro-segregation, and corresponds to where the mixture exhibit a percolation of the two species domains. In this paper, it is shown that two extrema occur in binary mixtures when one species forms "meta-particle" aggregates, the latter which act as a meta-species, and have their own concentration fluctuations, hence their own KBI extremum. This "meta-extremum" occurs at low concentration of the aggregate-forming species (such as alcohol in alkane), and is independant of the other usual extremum observed at mid volume fraction occupancy. These systems are a good illustration of the concept of the duality between concentration fluctuations and micro-segregation.

References in corpus (4)

• Canonical sampling through velocity-rescaling
• Clustering and Micro-immiscibility in Alcohol-Water Mixtures: Evidence from Molecular Dynamics Simulations
• Fluctuating micro-heterogeneity in water - tert-butyl alcohol mixtures and lambda-type divergence of the mean cluster size with phase transition-like multiple anomalies
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Cited by in corpus (1)

• Robust Kirkwood-Buff inversion in complex mixtures via reciprocal-space methods