Function rest::basis_io::cint_norm_factor

pub fn cint_norm_factor(iang: i32, alpha: f64) -> f64

Normalization factor for GTO radial part g=r^l e^{-\alpha r^2}

\frac{1}{\sqrt{\int g^r r^2 dr}} = \sqrt{\frac{2^{2l+3} (l+1)! (2a)^{1+1.5}}{(2l+2)!\sqrt{\pi}}}

Ref: H. B. Schlegel and M. J. Frisch, Int. J. Quant. Chem., 54(1995, 83-87)

This part is absorbed in the BasCell.coefficients for libcint, which, however, should be removed for numerical integration used.