Function stopping_power_ev_per_m 

pub fn stopping_power_ev_per_m(
    table: &CrossSectionTable,
    i: usize,
) -> Option<f64>

The stopping power λ⁻¹ ⟨W⟩ (eV/m) of row i of an energy-loss table, with ⟨W⟩ from mean_loss_ev; zero for a zero-rate row. None if i is out of range.