Wavefunctions and autoionisation of doubly excited states in momentum space

The authors report results on the wavefunction representation of doubly excited states of He and on their autoionisation probability amplitudes in momentum space. These are presented in terms of conditional probability density and differential transition amplitude plots. The correlated momentum wavefunctions are obtained by Fourier-transforming position wavefunctions computed by multiconfigurational Hartree-Fock and variational procedures. Special techniques are developed for the Fourier transform of the numerical Hartree-Fock scattering orbitals. The differential transition amplitude plots lead to the same conclusions regarding the mechanism of autoionisation as did the previous work in position space.