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DY: Dynamik und Statistische Physik

DY 16: Growth Processes and Surface Properties

DY 16.8: Vortrag

Montag, 27. März 2006, 18:00–18:15, H\"UL 186

Heat capacity of quasi-one-dimensional atomic adsorbates deposited in the groves of carbon nanotube bundles — •Konstantin Chishko, Tatiana Antsygina, and Igor Poltavsky — B. Verkin Institute for Low Temperature Physics and Engineering, 47 Lenin Ave., Kharkov 61103, Ukraine

The model taking into account both the formation of one-dimensional (1D) condensate at the bottom of the external grooves on carbon nanotube bundles and also the promotion of two secondary 1D chains over primary one (three-chain quasi-one-dimensional structure) is developed to describe the thermodynamics of rare gas adsorption on the nanobundle surface. The Gibbs free energy and the heat capacity of the system under study have been obtained within a universal lattice gas approach using both two-time Green functions and transfer matrix methods with regard to interparticle interactions in the primary and secondary chains. So, the model is adequate for treatment of a rather wide range of coverages on the initial stage of deposition. The heat capacity has been found as functions of both temperature T and low-dimensional adsorbate density n_ads at different values of interpartical energies and the interaction energy between adsorbed atoms and the substrate nanobundle. As a function of n_ads, the heat capacity demonstrates non-monotonic behavior with peaks localized near n_ads≃ 1 and n_ads≃ 3 which correspond to completed occupation of the positions in the primary and secondary chains. The height and width of the peaks are determined by the magnitudes of the interaction energies in the system. All the effects predicted by the theory are accessible for the experimental observation.