Van der Waals surface research use of a model showing the van der Waals surfaces of molecules. Related to the title concept are the ideas of a "van der Waals volume", V, and a "van der Waals surface area," abbreviated variously as A, vdWSA, VSA, and WSA. A van der Waals surface area is an abstract conception of the surface area of atoms or molecules from a mathematical estimation, either computing it from first principles or by integrating over a corresponding van der Waals volume. In simplest case, for a spherical monatomic gas, it is simply the computed surface area of a sphere of
Volume element formula_25. In coordinates, where formula_27 is the determinant of the metric tensor "g" written in the coordinate system. A simple example of a volume element can be explored by considering a two-dimensional surface embedded in "n"-dimensional Euclidean space. Such a volume element is sometimes called an "area element". Consider a subset formula_28 and a mapping function thus defining a surface embedded in formula_30. In two dimensions, volume is just area, and a volume element gives a way to determine the area of parts of the surface. Thus a volume element is an expression of the form that allows one to