xnn.ffnn.models.reaxff.nonbonded_taper#

xnn.ffnn.models.reaxff.nonbonded_taper(r, cutoff)[source]#

The 7th-order ReaxFF nonbonded taper Tap(r).

Tap = 1 - 35 (r/rc)^4 + 84 (r/rc)^5 - 70 (r/rc)^6 + 20 (r/rc)^7 is 1 at r = 0 and has zero value and slope at the cutoff. Used for the van der Waals, Coulomb and EEM kernels.

Parameters:

r (Tensor) – Interatomic distances.
cutoff (float) – The nonbonded cutoff radius rc.

Returns:

Taper values.

Return type:

Tensor