soft_sphere_pair_force

torch_sim.models.soft_sphere.soft_sphere_pair_force(dr, zi, zj, sigma=1.0, epsilon=1.0, alpha=2.0)[source]

Soft-sphere pair force (negative gradient of energy).

F(r) = (ε/σ) (1 - r/σ)^(α-1) for r < σ, else 0

Parameters:

  • dr (Tensor) – Pairwise distances.

  • zi (Tensor) – Atomic numbers of first atoms (unused).

  • zj (Tensor) – Atomic numbers of second atoms (unused).

  • sigma (Tensor | float) – Interaction diameter. Defaults to 1.0.

  • epsilon (Tensor | float) – Energy scale. Defaults to 1.0.

  • alpha (Tensor | float) – Repulsion exponent. Defaults to 2.0.

Returns:

Pair force magnitudes.

Return type:

Tensor