Dipak H. Oza

Ionization of hydrogen atoms by electron impact

Abstract Cross sections for the ionization of hydrogen atoms by electron impact have been computed for incident energies from threshold up to 54 eV. A projection technique has been used in conjunction with a variational pseudostate calculation.

Resonance parameters of the 1De doubly excited states of helium

Abstract The resonance parameters of the lowest three 1 D e autoionization states of the helium atom are calculated using a 14-state close-coupling approximation and by the complex coordinate rotation method using a wavefunction with 316 CI-type bases. The energy values by the two methods are in excellent agreement. The width for the 2p 21 D e state by both methods agrees with that of a recent experiment of Berry et al.

Numerical solution of the Schroedinger equation with a non-local exchange kernel

Abstract We describe the linear algebraic method for the numerical solution of the integral form of theScoroedinger equation with a nonlocal exchange kernel. We show explicitly the implementation of Newton-Cotes quadrature formulae of high order in order to account properly for the discontinuities arising in the derivative of the integrands originating from the two-particle Greens functions and the nonlocal kernels. The proposed technique is backed by numerical examples from scattering theory—scattering by a Yukawa potential and electron scattering by hydrogenic ions in the static-exchange approximation. The method is found to be efficient and numerically stable.