calculation of force

[藤岡芳弥]

Dear Nong

Do you include in the calculation the influence of the force received from atoms outside the cutoff range when calculating force with Predict?

I calculated forces working on individual atoms of force with predictions of aenet.

I added  "write" sentences to the program of aenet and output the neighborlist of the atoms of the atom of interest and the force received from each surrounding atom.

I thought that the influence of the force received from atoms outside the cutoff zone would be zero, but aenet  treats some  of extremely remote atoms as neighboring atoms and the force received from that atom was not calculated as zero.

Is this due to the algorithm of aenet?

Best,

Fujioka

[Nongnuch Artrith]

Dear Fujioka,

The forces acting on the reference atom (i) depend on the other atoms within 2x of the radial cutoff of the local atomic environment.  In other words, the cutoff for the forces is 2x the cutoff of the energy.

This is a result of the analytic derivative of the ANN potential.  The derivatives of the energies of all atoms (j) having atom (i) inside their cutoff sphere enter the force F that acts on atom (i).  Thus, the force depends on the positions of all atoms inside a sphere of radius 2xRcut.

For more details, please see equation (11), Fig. 12 and Fig. 13, and the related discussion in the attached paper (Artrith and Behler, Phys. Rev. B 85, 2012, 045439: https://doi.org/10.1103/PhysRevB.85.045439.

Please let me know if you have further questions.

Best,
Nong

[Yoshihisa Fujioka]

Dear Nong

Thanks to you,I was able to solve the doubt.

Best,

Fujioka