Constraint-based, Single-point Approximate Kinetic Energy Functionals

Details Constraint-based, Single-point Approximate Kinetic Energy Functionals Constraint-based, Single-point Approximate Kinetic Energy Functionals

2008-09-27

arxiv.org/abs/0809.4798v1

Physics

Condensed Matter

Materials Science

16 pages, 9 figures, 2 tables, submitted to Phys. Rev. B

Scientific paper

We present a substantial extension of our constraint-based approach for development of orbital-free (OF) kinetic-energy (KE) density functionals intended for the calculation of quantum-mechanical forces in multi-scale molecular dynamics simulations. Suitability for realistic system simulations requires that the OF-KE functional yield accurate forces on the nuclei yet be relatively simple. We therefore require that the functionals be based on DFT constraints, local, dependent upon a small number of parameters fitted to a training set of limited size, and applicable beyond the scope of the training set. Our previous "modified conjoint" generalized-gradient-type functionals were constrained to producing a positive-definite Pauli potential. Though distinctly better than several published GGA-type functionals in that they gave semi-quantitative agreement with Born-Oppenheimer forces from full Kohn-Sham results, those modified conjoint functionals suffer from unphysical singularities at the nuclei. Here we show how to remove such singularities by introducing higher-order density derivatives. We give a simple illustration of such a functional used for the dissociation energy as a function of bond length for selected molecules.

Affiliated with

Also associated with

No associations

Rating

Constraint-based, Single-point Approximate Kinetic Energy Functionals does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Constraint-based, Single-point Approximate Kinetic Energy Functionals, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Constraint-based, Single-point Approximate Kinetic Energy Functionals will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-353399