We report new results of triple differential cross sections for the single ionization of helium by 1-KeV electron impact at the ejection energy of 10 eV. Investigations have been made for both the perpendicular plane and the plane perpendicular to the momentum transfer geometries. The present calculation is based on the threewCoulomb wave function. Here we have also incorporated the effect of target polarization in the initial state. A comparison is made between the present calculation with the results of other theoretical methods and a recent experiment [Diirr M, Dimopoulou C, Najjari B, Dorn A, Bartschat K, Bray I, Fursa D V, Chen Z, Madison D H and Ullrich J 2008 Phys. Rev. A 77 032717]. At an impact energy of 1 KeV, the target polarization is found to induce a substantial change of the cross section for the ionization process. We observe that the effect of target polarization plays a dominant role in deciding the shape of triple differential cross sections.
The isotopic effect on nuclear dynamics in Coulomb explosion for various initial vibrational states of H_(2)^(+) and HD+in intense laser(80 fs,800 nm,I=6.8×10^(13)W/cm^(2)) is theoretically investigated by numerically solving the time-dependent Schrodinger equation.The calculated results confirm that the effect we discussed by paying close attention to the comparative analysis of peak locations in the nuclear kinetic-energy-release spectra largely depends on the selection of the initial vibrational states.Furthermore,it is the special isotope effect case about the vibrational state v=5 that has been studied in depth.We also discuss the time-dependent spectrum atυ=7,which can reveal the difference in nuclear wavepacket motion between H_(2)^(+) and HD+in the time region in which charge-resonance enhanced ionization takes place.
