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