Hard spheres are widely used as model particles in the statistical mechanical theory of fluids and solids. They are defined simply as impenetrable spheres that cannot overlap in space. They mimic the extremely strong ("infinitely elastic bouncing") repulsion that atoms and spherical molecules experience at very close distances. Hard spheres systems are studied by analytical means, by molecular dynamics simulations, and by the experimental study of certain colloidal model systems.
Beside being a model of theoretical significance, the hard-sphere system is used as a basis in the formulation of several modern, predictive Equations of State for real fluids through the SAFT approach, and models for transport properties in gases through Chapman-Enskog Theory.
Hardspheres are widely used as model particles in the statistical mechanical theory of fluids and solids. They are defined simply as impenetrable spheres...
sized hardspheres. Hardspheres are characterized as non-interacting and impenetrable spheres. These two fundamental properties of hardspheres are described...
2 R {\displaystyle b>2R} , where the colliding nuclei are viewed as hardspheres with radius R {\displaystyle R} .[citation needed] Because the color...
In geometry, a sphere packing is an arrangement of non-overlapping spheres within a containing space. The spheres considered are usually all of identical...
atoms nor ions have sharp boundaries, they are treated as if they were hardspheres with radii such that the sum of ionic radii of the cation and anion gives...
used in engineering practice. If one models gas molecules as elastic hardspheres (with mass m {\displaystyle m} and diameter σ {\displaystyle \sigma }...
of a container is occupied by the spheres. The problem of predicting theoretically the random close pack of spheres is difficult mainly because of the...
of hardspheres. This is a model of perfectly hardspheres in thermal motion, and is a simple model of some colloids. For the crystallization of hard spheres...
the seven planetary spheres contained other secondary spheres within them. The planetary spheres were followed by the stellar sphere containing the fixed...
{\partial \rho }{\partial p}}\right)} . In the hardsphere model, the particles are described as impenetrable spheres with radius R {\displaystyle R} ; thus,...
terms of the mean free path. Typically, gas molecules do not behave like hardspheres, but rather attract each other at larger distances and repel each other...
packing of hardspheres with various sizes makes that smaller spheres have larger probability to move downwards by gravitation than larger spheres. The phenomenon...
Sphere packing in a cylinder is a three-dimensional packing problem with the objective of packing a given number of identical spheres inside a cylinder...
per unit time. In an ideal gas, assuming that the species behave like hardspheres, the collision frequency between entities of species A and species B...
if all other knowledge was lost. By modeling matter as collections of hardspheres, it is possible to describe the kinetic theory of gases, upon which classical...
proposed stellar engine designs are based on the Dyson sphere. A precursor to the concept of Dyson spheres was featured in the 1937 novel Star Maker by Olaf...
pellet to hardspheres. The raw material is rolled into a ball, then fired in a kiln or in travelling grate to sinter the particles into a hardsphere. The...
the crystal phase in a system of hardspheres, which is a simple model of colloids consisting of perfectly hardspheres in thermal motion. The agreement...
molecular interaction model; here we take the hardspheres model, which is the simplest. In the hardspheres model, the collision probability for the pair...
will collide, and experience a very high repulsive force (modelled by Hardspheres) which is a much stronger force than the attractions, so that any attraction...
\end{cases}}} r is the distance between the centers of the spheres and d is the distance where the hardspheres touch each other (twice the Van der Waals radius)...
The van der Waals radius, rw, of an atom is the radius of an imaginary hardsphere representing the distance of closest approach for another atom. It is...