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DMol 3 is a commercial (and academic) software package which uses density functional theory with a numerical radial function [1] basis set to calculate the electronic properties of molecules, clusters, surfaces and crystalline solid materials [2] from first principles.
Density is an intensive property in that increasing the amount of a substance does not increase its density; rather it increases its mass. Other conceptually comparable quantities or ratios include specific density , relative density (specific gravity) , and specific weight .
The interest stems from that accurate measurements of the unit cell volume, atomic weight and mass density of a pure crystalline solid provide a direct determination of the Avogadro constant. [3] The CODATA recommended value for the molar volume of silicon is 1.205 883 199 (60) × 10 −5 m 3 ⋅mol −1, with a relative standard uncertainty of ...
For any substance, the number density can be expressed in terms of its amount concentration c (in mol/m 3) as = where N A is the Avogadro constant. This is still true if the spatial dimension unit, metre, in both n and c is consistently replaced by any other spatial dimension unit, e.g. if n is in cm −3 and c is in mol/cm 3 , or if n is in L ...
The kilogram per cubic metre (symbol: kg·m −3, or kg/m 3) is the unit of density in the International System of Units (SI). It is defined by dividing the SI unit of mass , the kilogram , by the SI unit of volume , the cubic metre .
The density may be portrayed in terms of an isosurface (isodensity surface) with the size and shape of the surface being given by the value (or percentage of enclosure) of the electron density. Spin density – The density, ρ spin ( r ), is defined as the difference in electron density formed by electrons of α spin, ρα( r ), and the ...
A special type of area density is called column density (also columnar mass density or simply column density), denoted ρ A or σ. It is the mass of substance per unit area integrated along a path; [ 1 ] It is obtained integrating volumetric density ρ {\displaystyle \rho } over a column: [ 2 ] σ = ∫ ρ d s . {\displaystyle \sigma =\int \rho ...
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