pub fn compute_pm3_gradient(
elements: &[u8],
positions: &[[f64; 3]],
) -> Result<Pm3GradientResult, String>Expand description
Compute PM3 analytical energy gradients.
Returns dE/dR in eV/Å for each atom, computed from the converged SCF density matrix using Hellmann-Feynman + Pulay corrections.