Chemistry — Atomic Structure (Bohr / Rydberg)

E_n = -\frac{13.6\ \text{eV}}{n^2}

\frac{1}{\lambda} = R_H\left(\frac{1}{n_1^2} - \frac{1}{n_2^2}\right)

r_n = \frac{n^2 \hbar^2}{m k e^2}

\Delta E = E_{n_2} - E_{n_1}