Island formation without attractive interactions

We show that adsorbates on surfaces can form islands even if there are no attractive interactions. Instead strong repulsion between adsorbates at short distances can lead to islands, because such islands increase the entropy of the adsorbates that are not part of the islands. We suggest that this mechanism cause the observed island formation in O/Pt(111), but it may be important for many other systems as well.Comment: 11 pages, 4 figure

Influence of surface diffusion on catalytic reactivity of spatially inhomogeneous surfaces mean field modeling

Kinetics of model catalytic processes proceeding on inhomogeneous surfaces is studied. We employ an extended mean-field model that takes into account surface inhomogeneities. The influence of surface diffusion of adsorbent on the kinetics of the catalytic process is investigated. It is shown that diffusion is responsible for differences in the reaction rate of systems with different arrangements of active sites. The presence of cooperative effects between inactive and active sites is demonstrated and the conditions when these effects are important are discussed. We show that basic catalytic phenomena on nonuniform surfaces can be studied with mean-field modeling methods.Comment: Submitted to Chemical Physics Letters. Includes supporting material in Appendice

Bridge-bonded adsorbates on fcc(100) and fcc(111) surfaces: a kinetic Monte Carlo study

Catalysis and Surface Chemistr

Morphology formation in binary mixtures upon gradual destabilisation

Spontaneous liquid-liquid phase separation is commonly understood in terms of phenomenological mean-field theories. These theories correctly predict the structural features of the fluid at sufficiently long time scales and wavelengths. However, these conditions are not met in various examples in biology and materials science where the mixture is slowly destabilised, and phase separation is strongly affected by critical thermal fluctuations. We propose a mechanism of pretransitional structuring of a mixture that approaches the miscibility gap and predict scaling relations that describe how the characteristic feature size of the emerging morphology decreases with an increasing quench rate. These predictions quantitatively agree with our kinetic Monte Carlo and molecular dynamics simulations of a phase-separating binary mixture, as well as with previously reported experimental observations. We discuss how these predictions are affected by non-conserved order parameters (e.g., due to chemical reactions or alignment of liquid-crystalline molecules), hydrodynamics and active transport

Secularist understandings of Pentecostal healing practices in Amsterdam:Developing an intersectional and post-secularist sociology of religion

The past decades have seen an intensification of debate around migrants, gender and sexuality. For the Netherlands, several authors have pointed out how this has given rise to a form of sexual nationalism whereby the idea of being a modern, progressive country is strongly linked to a program of liberal sexual values and offset against a presumably 'backward' migrant who is 'still' religious and traditional. In this article, the author analyses how these dynamics played out in the controversy around HIV-healings or homo healings supposedly taking place in Pentecostal churches in Amsterdam. Media attention highlighted the theme of homosexuality while forgetting the interests of women. This article shows that the sexual nationalism scheme was also operative here, and proposes further developing existing approaches as intersectional 'post-secularist' sociological perspectives aimed at unearthing the ways narratives of modernity, secularization and sexual nationalism structure attitudes towards migrant and religious actors both in social scientific research agendas and among societal actors