This routine computes the lowest-order normalized hydrogenic bound state radial wavefunction \(R_1 := 2 Z \sqrt{Z} \exp(-Z r)\).
This routine computes the \(n\)-th normalized hydrogenic bound state radial wavefunction,
where \(L^a_b(x)\) is the generalized Laguerre polynomial (see Laguerre Functions). The normalization is chosen such that the wavefunction \(\psi\) is given by \(\psi(n,l,r) = R_n Y_{lm}\).