Polarised Electron Study of Angular Momentum Coupling in the Neon 3p States

The excitation of the 2p5 3p[]3 and 2p5 3p′[½]1 states in the neon 3p manifold by transversally polarised electrons is studied in the electron energy region near threshold and beyond. The spin-orbit and exchange interactions during the excitation are explored by the measurement of integrated Stokes parameters P2 and P3 for the decay radiation from these states. Experimental evidence is given for the breakdown of LS coupling for the neon 3p (J = 1) state and the important role of spin–orbit and exchange interactions of the atomic electrons for the excitation of the state. Negative ion resonances strongly influence the polarisations of the decay radiations.