Rydberg formula (Rydberg):
A formula which define all of the characteristics of hydrogen's spectrum, comprising the Lyman, Paschen, Balmer, Pfund series and Brackett,.
For the transition among an electron into orbital m to one into orbital n (or the reverse), the wavelength lambda included is given through
1/lambda = R (1/m^{2} - 1/n^{2}).