Calculated Born and four-state cross sections of low lying Ar levels excited by proton and electron impact

The excitation of (3p)54s and (3p)54p levels of Ar is investigated by use of the Born approximation and a four-state calculation including 1S0(3p)6, 1S0(3p)54p and P1(3p)54s (M=0,1). HF-type wavefunctions are used. The spin-orbit coupling is treated in a rather semiempirical way.