Formula of MSD in LAMMPS

Does the formula for mean squared displacements include the 6 in the denominator or is it without the 6 as shown below?


Ankit Roy
Graduate Research Assistant,
Packard Lab 375,
Mechanical Engineering and Mechanics,
Lehigh University

there is no factor of 6 in mean squared displacement. it is computed exactly as in the quoted formula.

you are probably referring to the derivation of the self-diffusion coefficient through the einstein relation (in 3 dimensions).

please see the example in the examples/DIFFUSE folder of the LAMMPS distribution (which demonstrates the computation of D in 2d, hence the factor 4, not 6).