In this work we analytically evaluate, for the first time, the exact canonical partition function for two interacting spherical particles into a spherical pore. The interaction with the spherical substrate and between particles is described by an attractive square-well and a square-shoulder potential. In addition, we obtain exact expressions for both the one particle and an averaged two particle density distribution. We develop a thermodynamic approach to few-body systems by introducing a method based on thermodynamic measures [I. Urrutia, J. Chem. Phys. 134, 104503 (2010)] for nonhard interaction potentials. This analysis enables us to obtain expressions for the pressure, the surface tension, and the equivalent magnitudes for the total and Gaussian curvatures. As a by-product, we solve systems composed of two particles outside a fixed spherical obstacle. We study the low density limit for a many-body system confined to a spherical cavity and a many-body system surrounding a spherical obstacle. From this analysis we derive the exact first order dependence of the surface tension and Tolman length. Our findings show that the Tolman length goes to zero in the case of a purely hard wall spherical substrate, but contains a zero order term in density for square-well and square-shoulder wall-fluid potentials. This suggests that any nonhard wall-fluid potential should produce a non-null zero order term in the Tolman length. © 2011 American Institute of Physics.
Documento: | Artículo |
Título: | Two interacting particles in a spherical pore |
Autor: | Urrutia, I.; Castelletti, G. |
Filiación: | Consejo Nacional de Investigaciones Cientficas y Técnicas Argentina (CONICET), Departamento de Física, Comisin Nacional de Energa Atmica, Av. Gral. Paz 1499 (RA-1650), San Martn, Buenos Aires, Argentina Instituto de Astronoma y Física Del Espacio (CONICET-UBA), Buenos Aires, Argentina Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Argentina |
Palabras clave: | Canonical partition function; Few body systems; First-order dependence; Fluid potentials; Gaussian curvatures; Hard walls; Interacting particles; Interaction potentials; Low density; Many-body systems; Spherical cavities; Spherical particle; Spherical pores; Spherical substrates; Square-well; Two particles; Zero order; Surface properties; Surface tension; Spheres |
Año: | 2011 |
Volumen: | 134 |
Número: | 6 |
DOI: | http://dx.doi.org/10.1063/1.3544681 |
Título revista: | Journal of Chemical Physics |
Título revista abreviado: | J Chem Phys |
ISSN: | 00219606 |
CODEN: | JCPSA |
PDF: | https://bibliotecadigital.exactas.uba.ar/download/paper/paper_00219606_v134_n6_p_Urrutia.pdf |
Registro: | https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00219606_v134_n6_p_Urrutia |