Hyperfine Structure Calculator

Calculate hyperfine splitting from electron-nucleus spin interaction

Hyperfine Structure: Hydrogen 1s

Quantum Numbers
J = 0.5, I = 0.5
Hyperfine Constant A
1420.405752 MHz
Total Hyperfine Splitting
1420.405752 MHz
Wavelength: 21.1066 cm
Hyperfine Levels (F = |J-I| to J+I)
F = 0: E = -1065.3043 MHz, degeneracy = 1
F = 1: E = 355.1014 MHz, degeneracy = 3
Number of Hyperfine Levels
2

Formulas Used

E_hfs = (A/2) * K

K = F(F+1) - I(I+1) - J(J+1)

F = |J-I|, |J-I|+1, ..., J+I

Hydrogen 21 cm line: 1420.405751768 MHz