{\displaystyle E_{hf}={\frac {\mu _{0}g_{p}e^{2}\hbar ^{2}}{3\pi m_{p}m_{e}a^{3}}}\left\{{\begin{matrix}+{\frac {1}{4}}&({\textrm {triplet}})\\-{\frac {3}{4}}&({\textrm {singlet}})\end{matrix}}\right.}