Above-threshold ionization of Ca and Sr atoms

We investigate the above-threshold ionization of Alkaline earth atoms Ca and Sr by a strong laser field in the tunneling regime. Hartree-Fock potential is used in the simulation. Volkov propagater is applied in obtaining the high energy photoelectron spectra. The effect of the orthogonality between the dyanmic electron and the core electron orbitas, and the effect of laser-induced core polarization are examined.