Radiative and relativistic effects in the decay of highly excited states in helium
A recent experimental study [J.-E. Rubensson et al., Phys. Rev. Lett. 83, 947 (1999)] measured a significant fluorescence yield of the He( 2lnl(')) photoexcited resonances, showing major qualitative differences from nonrelativistic predictions. We present a further theoretical study of these states, and perform R-matrix multichannel quantum defect theory calculations to extract fluorescence and ionization cross sections. These theoretical results are in excellent agreement with newer, higher-resolution measurements. Radiative and spin-orbit effects are quantified and shown to play an important role in the overall characterization of highly excited states.
Gorczyca
TW
Department of Physics, Western Michigan University, Kalamazoo, Michigan 49008-5151, USA.
Rubensson
JE
Sathe
C
Strom
M
Agaker
M
Ding
D
Stranges
S
Richter
R
Alagia
M