INVESTIGADORES
RAMIREZ PASTOR Antonio Jose
artículos
Título:
Quasi-chemical approximation for polyatomics: statistical thermodynamics of adsorption
Autor/es:
M. DÁVILA; F. ROMÁ; J. L. RICCARDO; A. J. RAMIREZ-PASTOR
Revista:
SURFACE SCIENCE
Referencias:
Año: 2006 vol. 600 p. 2011 - 2025
ISSN:
0039-6028
Resumen:
The statistical thermodynamics of interacting polyatomic adsorbates (k-mers) on homogeneous surfaces was developed on a generalization
in the spirit of the lattice-gas model and the quasi-chemical approximation (QCA). The new theoretical framework is obtained
by combining (i) the exact analytical expression for the partition function of non-interacting linear k-mers adsorbed in one dimension
and its extension to higher dimensions, and (ii) a generalization of the classical QCA in which the adsorbate can occupy more than
one adsorption site. The coverage and temperature dependence of the Helmholtz free energy, chemical potential, configurational
entropy, configurational energy, isosteric heat of adsorption and specific heat are given. The formalism reproduces the classical QCA
for monomers, leads to the exact statistical thermodynamics of interacting k-mers adsorbed in one dimension, and provides a close
approximation for two-dimensional systems accounting multisite occupancy. Comparisons with analytical data from BraggWilliams
approximation (BWA) and Monte Carlo simulations are performed in order to test the validity of the theoretical model. The resulting
thermodynamic description is significantly better than the BWA and still mathematically handable.k-mers) on homogeneous surfaces was developed on a generalization
in the spirit of the lattice-gas model and the quasi-chemical approximation (QCA). The new theoretical framework is obtained
by combining (i) the exact analytical expression for the partition function of non-interacting linear k-mers adsorbed in one dimension
and its extension to higher dimensions, and (ii) a generalization of the classical QCA in which the adsorbate can occupy more than
one adsorption site. The coverage and temperature dependence of the Helmholtz free energy, chemical potential, configurational
entropy, configurational energy, isosteric heat of adsorption and specific heat are given. The formalism reproduces the classical QCA
for monomers, leads to the exact statistical thermodynamics of interacting k-mers adsorbed in one dimension, and provides a close
approximation for two-dimensional systems accounting multisite occupancy. Comparisons with analytical data from BraggWilliams
approximation (BWA) and Monte Carlo simulations are performed in order to test the validity of the theoretical model. The resulting
thermodynamic description is significantly better than the BWA and still mathematically handable.k-mers adsorbed in one dimension
and its extension to higher dimensions, and (ii) a generalization of the classical QCA in which the adsorbate can occupy more than
one adsorption site. The coverage and temperature dependence of the Helmholtz free energy, chemical potential, configurational
entropy, configurational energy, isosteric heat of adsorption and specific heat are given. The formalism reproduces the classical QCA
for monomers, leads to the exact statistical thermodynamics of interacting k-mers adsorbed in one dimension, and provides a close
approximation for two-dimensional systems accounting multisite occupancy. Comparisons with analytical data from BraggWilliams
approximation (BWA) and Monte Carlo simulations are performed in order to test the validity of the theoretical model. The resulting
thermodynamic description is significantly better than the BWA and still mathematically handable.k-mers adsorbed in one dimension, and provides a close
approximation for two-dimensional systems accounting multisite occupancy. Comparisons with analytical data from BraggWilliams
approximation (BWA) and Monte Carlo simulations are performed in order to test the validity of the theoretical model. The resulting
thermodynamic description is significantly better than the BWA and still mathematically handable.