# negative hydrogen ion

## The calculation of photoionization cross-section of negative hydrogen ions in the Born approximation

It is shown that the two-electron wave function of the system "hydrogen atom + photoelectron" in the Born approximation provides high accuracy of the photoionization process cross-section calculation of negative hydrogen ion.  The partial cross-sections, which correspond to different reaction ns-channels'' in the scale of photoelectron energy and the scale of wavelengths are calculated.  The comparisons with the results of other authors which obtained by other methods are performed.

## The shell model of electron structure of negative hydrogen ion

In the frame of non-relativistic approximation, a compact approximate solution of the Schrödinger equation for the ion of $H^{-}$ has been obtained in the form of product for Legendre polynomials and variational functions of the Schull--Löwdin type. The accuracy of calculation of ion energy is of the same order that the results obtained using the multiparametric functions of Hylleraas and Pekeris.