pub const HBAR_EV_S: f64 = 6.582_119_569e-16;
Planck constant (reduced, ħ) in eV·s.
Derived from h = 6.626_070_15e-34 J·s (exact, 2019 SI) and e = 1.602_176_634e-19 C (exact): ħ = h / (2π·e). Rounded to 10 significant figures.