Both lattice dynamics (LD) and molecular dynamcis (MD) can be adopted to simulate/model crytal structure, thermodynamcis and atom transport, what's the difference between two methods? what's the advantages and disadvantages?
FYI:
Article Application of Lattice Dynamics and Molecular Dynamics Techn...
Both techniques involve solving Newton’s Laws of Motion but differ in the approximations made. Lattice dynamics involves analytical solution of the equations of motion followed by the use of a statistical mechanical treatment to obtain the thermodynamic properties, such as free-energy and heat capacity. The central assumption of LD is that the vibrational modes in the material are harmonic. Hence this approach cannot be used reliably for liquids but has been used extensively for modeling the thermal properties of solids.
In contrast, molecular dynamics uses a numerical solution to the equations of motion where the atom positions and velocities are updated regularly and hence is not constrained to solids and can be readily applied to fluids. The consequence of using a numerical solution is that it requires much more computer CPU time, particularly when evaluating thermodynamic data. However, by not making assumptions about the potential energy surface, MD has the potential to be more accurate.
Lattice dynamics is used to analyze the vibrations and phonons emerging
when there is a crystaline structure of the material, with possible variations
depending on the complexity of the structure or deviations from perfect crystaline structure.
A lattice is an ordered structure of atoms, making up a crystal say.
Ref , Solid state text books
Molecular dynamics analyzes say the motion of independent molecules in a gas, or could possibly refer to the allowed motions within the molecule itself.
I think fairly close to Ma s answer overall.
Ref. Ideal gases, Maxwell distribution.
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