Polarized electron inner-shell ionization-with-excitation of zinc atoms

Abstract

The ionization-with-excitation collision process, from the ground 3d104s2 1S0 state to the ionic 3d94s2 2D3/2 state of the zinc atom, has been investigated using incident polarized electrons with near-threshold energies. The observed Stokes parameters of the emitted 589.4 nm photon show that the residual ion is aligned and oriented. These observations also indicate directly the electron exchange effects in the inner-shell ionization-with-excitation process. From these measured Stokes parameters the normalized state multipoles, the electric quadrupole moment of the orbital angular momentum and the magnetic dipole moment of the spin angular momentum of the excited ionic state are derived. The combination of electron exchange and fine-structure coupling enable a net negative angular momentum transfer to the atomic system. The contributions from various partial waves and from the spin-orbit interaction to the ionization-with-excitation process are discussed.

Investigation of the behaviour of the Sherman function for elastic electron scattering from Kr and Xe

“…The measurements of spin-related scattering have been carried out using the spin-polarized electron scattering apparatus at UWA. The techniques have been developed over many years with a series of measurements on elastic scattering (Napier et al 2007), excitation (Pravica et al 2007a), ionization-withexcitation in inert gases (Yu et al 2001(Yu et al , 2006 and zinc atoms (Pravica et al 2007b) for spin-polarized and non-polarized electron beams. Here, the determination of the Sherman function S is made from observations of the difference of the number of elastically scattered spin-up N ↑ and spin-down N ↓ electrons after reversal of the spin polarization from the spin source.…”

Spin and Electron Correlation Effects in Excitation of 3d Metal Atoms

“…Experiments with spin polarized electrons [8,9,10] offer an additional strength to experimental studies with the possibility to explore the influence of the spin orbit and exchange interaction as well as momentum couplings. Our investigations in Perth show that temporary negative ions involving a single electron excitation from the 3d orbital in zinc are strongly influencing electron scattering.…”

The 1S–1P electron excitations of Zn at small scattering angles

“…Zinc is an atom that has been driving a lot of interest recently, starting from investigations of collisional crosssections [1,2], ionization phenomena [3][4][5] to isotope abundances and the concentrations in humans [6]. There are number of theoretical studies of optical oscillator strengths [7,8] and very few electron excitation cross-section calculations [9].…”