Author
William A. Steele
Other affiliations: Universidade Federal do Rio Grande do Sul, RWTH Aachen University, University of Padua
Bio: William A. Steele is an academic researcher from Pennsylvania State University. The author has contributed to research in topics: Adsorption & Monolayer. The author has an hindex of 43, co-authored 193 publications receiving 6868 citations. Previous affiliations of William A. Steele include Universidade Federal do Rio Grande do Sul & RWTH Aachen University.
Topics: Adsorption, Monolayer, Diatomic molecule, Polarizability, Graphite
Papers published on a yearly basis
Papers
More filters
TL;DR: In this paper, the potential energy of a gas atom interacting with a solid having a surface made up of single type of exposed lattice plane can be expressed as a Fourier series in the position variables in the plane parallel to the surface.
1,379 citations
TL;DR: In this article, the rotational motion of rigid molecules in liquids obeying classical mechanics is considered and the equations of motion for a spherical top have solutions of the form of the Langevin equation.
Abstract: The orientational motion of rigid molecules in liquids obeying classical mechanics is considered. The equations of motion of these systems are Euler's equations. It is assumed that the torque on a molecule can be represented by a friction term proportional to angular velocity plus a randomly fluctuating torque. It is then shown that the equations of motion for a spherical top have solutions of the form of the solutions of the Langevin equation. The components of the diagonalized rotational friction constant tensor are given as time integrals of the autocorrelation functions of the components of the angular velocity and an approximate expression is obtained which gives the rotational friction constants in terms of ensemble averages of the angular derivatives of the intermolecular potential function. A differential equation is derived for the time‐dependent distribution function for the Eulerian angle displacements. The solutions of this equation can be written in terms of the solutions of the Schrodinger equation for the asymmetric top multiplied by exponentially decaying functions of time. Molecules possessing elements of symmetry in their interaction potential functions are considered, and it is shown that the components of the rotational friction tensor approach zero in these systems and that the rotational motion over relatively long time intervals is then determined by the inertial terms in the equation of motion. The application of these results to the theory of rotational nuclear magnetic and dielectric relaxation in liquids is briefly discussed.
202 citations
179 citations
TL;DR: In this paper, the normalized angular autocorrelation functions which appear in the theories of rotational nuclear magnetic and dielectric relaxation are considered in the light of the results presented in Paper I of this series.
Abstract: The normalized angular autocorrelation functions which appear in the theories of rotational nuclear magnetic and dielectric relaxation are considered in the light of the results presented in Paper I of this series. The time‐dependent spherical harmonics in the equations for the autocorrelation functions are written as functions of the molecular Eulerian angular displacements. The time dependence of the autocorrelation functions is calculated using the distribution functions obtained in I, and it is shown that the results are strongly dependent upon the magnitude of the components of the diagonalized rotational friction tensor. If all components are large and unequal, five relaxation times appear in the autocorrelation function for nuclear relaxation and three times appear in the function for dielectric relaxation. If one or more of the components are small, the autocorrelation functions are found to be dependent upon the inertial terms in the molecular equations of motion. Autocorrelation functions are ev...
161 citations
TL;DR: In this article, the second and third virial coefficients of a classical monatomic adsorbate are put into a form suitable for numerical evaluation, which is accomplished by expanding the Boltzmann factors in the general expressions as Fourier series in the translational symmetry coordinates of the surface lattice.
160 citations
Cited by
More filters
Book•
01 Jan 1971
TL;DR: In this paper, Ozaki et al. describe the dynamics of adsorption and Oxidation of organic Molecules on Illuminated Titanium Dioxide Particles Immersed in Water.
Abstract: 1: Magnetic Particles: Preparation, Properties and Applications: M. Ozaki. 2: Maghemite (gamma-Fe2O3): A Versatile Magnetic Colloidal Material C.J. Serna, M.P. Morales. 3: Dynamics of Adsorption and Oxidation of Organic Molecules on Illuminated Titanium Dioxide Particles Immersed in Water M.A. Blesa, R.J. Candal, S.A. Bilmes. 4: Colloidal Aggregation in Two-Dimensions A. Moncho-Jorda, F. Martinez-Lopez, M.A. Cabrerizo-Vilchez, R. Hidalgo Alvarez, M. Quesada-PMerez. 5: Kinetics of Particle and Protein Adsorption Z. Adamczyk.
1,870 citations
TL;DR: This review presents in brief the history of adsorption and highlights the progress in theoretical description of the phenomenon under consideration, as well as presenting some of the latest important results and giving a source of up-to-date literature on it.
1,799 citations
TL;DR: In this article, the pore size distributions derived from adsorption isotherms of micro- and mesoporous materials are identified and discussed based on new results and examples reported in the recent literature.
1,775 citations
TL;DR: A review of the current state of knowledge of phase separation and phase equilibria in porous materials can be found in this article, where the focus is on fundamental studies of simple fluids and well-characterized materials.
Abstract: We review the current state of knowledge of phase separation and phase equilibria in porous materials. Our emphasis is on fundamental studies of simple fluids (composed of small, neutral molecules) and well-characterized materials. While theoretical and molecular simulation studies are stressed, we also survey experimental investigations that are fundamental in nature. Following a brief survey of the most useful theoretical and simulation methods, we describe the nature of gas‐liquid (capillary condensation), layering, liquid‐liquid and freezing/melting transitions. In each case studies for simple pore geometries, and also more complex ones where available, are discussed. While a reasonably good understanding is available for phase equilibria of pure adsorbates in simple pore geometries, there is a need to extend the models to more complex pore geometries that include effects of chemical and geometrical heterogeneity and connectivity. In addition, with the exception of liquid‐liquid equilibria, little work has been done so far on phase separation for mixtures in porous media.
1,436 citations
TL;DR: In this paper, the potential energy of a gas atom interacting with a solid having a surface made up of single type of exposed lattice plane can be expressed as a Fourier series in the position variables in the plane parallel to the surface.
1,379 citations