Molecular diffusion constant

Steep concentration gradients cause large fluxes of particles. Small gradients cause small fluxes. Also, the larger the diffusion constant, the higher the flux, for a given gradient. Table 18.1 lists some molecular diffusion constants. 

Given that, in most laboratory experiments the gas flow was laminar, the diffusion time can be estimated using the molecular diffusion constant. The only exceptions are the experiments on the pilot plant described in [76], the flow in which was turbulent. 

In any computational (or experimental) study of interfaces, the properties of interest can be divided into three categories structure - such as the length scale over which the microscopic density changes from solid-like to liquid-like values as the interface is crossed dynamics - for example, the variation of the molecular diffusion constant through the interfacial region ... 

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