Ionization and excitation of np sup 4 (n+1)p levels of noble gases by electron impact

Absolute cross sections for simultaneous ionization and excitation by electron impact of some Ne II(2{ital p}{sup 4}3p), Ar II(3p{sup 4}4p), and Kr II(4{ital p}{sup 4}5p) levels from the atomic ground state have been measured with the optical method. Dependence of the emission cross sections on electron energy was studied between threshold and 1000 eV. The measured maximum cross sections for level excitation at the maximum are in the range (19.0--4.7){times}10{sup {minus}20} cm{sup 2} for Ne II, (97.4--71.7){times}10{sup {minus}20} cm{sup 2} for Ar II, and (98.7--69.2){times}10{sup {minus}20} cm{sup 2} for Kr II.