The asymmetry parameter β for fluorescence photons emitted during the radiative decay of the sp2,n+(1Po), sp2,n−(1Po), 2pnd(1Po) and 2pnd(3Do) series of helium doubly excited states, formed by the absorption of linearly polarized synchrotron radiation, has been measured. The results are compared with recent theoretical calculations (Žitnik et al 2002 Phys. Rev. A 65 032520). At high n the β parameter is shown to increase and oscillate due to the excitation of triplet states, optically accessible from the helium ground state due to spin–orbit effects.
|Journal||Journal of Physics B: Atomic, Molecular and Optical Physics|
|Publication status||Published - 2003|
Lambourne, J. G., Penent, F., Lablanquie, P., Hall, R. I., Ahmad, M., Zitnik, M., ... Coreno, M. (2003). Angular distribution of the fluorescence of helium doubly photo-excited states converging on the He+ (N=2)ionization threshold. Journal of Physics B: Atomic, Molecular and Optical Physics, 36(21), 4351-4359. https://doi.org/10.1088/0953-4075/36/21/013