Polarization-correlation stokes parameters for the quadrupole 2p⁶-2p⁵3p j = 2 transitions in neon

First calculations of the polarization-correlation Stokes parameters P, (t = 1, 2, 3, 4) for the quadrupole excitations by electron impact in heavy inert gases are carried out talcing the 2p⁵3p 7 = 2 states of neon as an example. The distorted-wave Bom approximation and the multichannel diffraction approximation are used and the sensitivity of the Pi parameters to different couplings is studied. The indirect dipole couplings via the resonance 2p⁵3s 7=1 levels cause a drastic rotation of the excitation amplitudes in the complex plane and strongly affect the Stokes parameters. The results are compared with recent measurements. The excitation cross sections are briefly discussed.