Energy levels of a hydrogen atom in a magnetic field

A finite-basis-set variational method with the two-limit basis functions proposed to calculate the states 1${\mathit{s}}_0$ and 2${\mathit{p}}_{\mathrm{-}1}$ by Chen and Goldman [Phys. Rev. A 45, 1722 (1992)] is used to calculate the energy levels of a hydrogen atom in a magnetic field. The accurate energy eigenvalues for the eigenstates with major quantum numbers less than or equal to 3 are obtained. The finite-basis-set method with the two-limit basis functions can be used to obtain accurate results not only for the ground state but also for any excited state.