pub fn natural_isotopes(z: u32) -> Vec<(u32, f64)>Expand description
All naturally occurring isotopes for element Z, as (A, fraction) pairs.
Returns an empty Vec for synthetic elements (e.g., Tc, Pm).
ยงExamples
let fe = endf_mat::natural_isotopes(26);
assert_eq!(fe.len(), 4); // Fe-54, Fe-56, Fe-57, Fe-58
let total: f64 = fe.iter().map(|(_, f)| f).sum();
assert!((total - 1.0).abs() < 0.01);