Abstract The normal “structureless” particle parameters are examined theoretically and experimentally. The results of calculations showing the agreement between finite size and point nucleus L-subshell particle parameters for M1, E1 and E2 transitions are given. The L 3 subshell interference particle parameters b 2(M1 + E2) and b 2(E1 + M2) in the region 49 ≦ Z ≦ 98, calculated with finite size (screening corrected) radial matrix elements are presented. For the L 3 shell, the b 4 particle parameters for M2 and E2 multipoles are also given. The point-nucleus model has been used for calculating the L-subshell particle parameters for E3 and M4 multipoles. For these multipoles, tables are given for Z = 49, 77 and 98 in the energy range 0.1 ≦ k ≦ 0.7. The use of the L-shell particle parameters and particle parameter ratio b 2(K)/ b 2(TL) for the determination of the mixing amplitude δ, and the sign of δ is discussed.