Some aspects of d-phase shifts behavior in the slow electron scattering on the alkaline earth atoms

Calculations of the phase shifts with polarization corrections in the slow electron scattering show that atoms Ca, Sr and Ba can be formed as negative ions. The value of the polarization potential have be determined by the absolute values of the matrix Σk for different transitions. Our calculations show existence of the Ramsauer's minimum and scattering length is negative. In the calculation of the matrix elements for the polarization interaction we take into account contributions from the monopole, dipole and quadrupole transitions. In diagram loop the excitation only from outside shells are taken into consideration. The wave functions of the excitation states are calculated in the ion field. Comparing the d-phase shifts for each element one can notice that the momentum at which σ2 starts to increase shifts towards lower values, and the rise becomes steeper with the increase of the charge of the nucleus. When taking into account the polarization potential, all phases St start to increase at lower k values than δ2HF, at following momenta: k = 0.35 au, k = 0.27 au and k 0.12 au. Therefore, we have the resonance behaviour of the d-wave cross section for the Sr and Ba atoms