Differential cross sections for electron impact excitation out of the ( ... 6s6p 1P1) state of barium

Differential cross sections for electron impact on excited state barium atoms have been measured for 20 eV incident electron energy and scattering angles of 5.5 degrees, 9 degrees, 13 degrees and 16 degrees. Results for the excitations (... 6s6p P-1(1)) -> X are presented with X (... 6s7s(1)S(0)), (... 6s7p(1)P(1)), (... 5d(2 1)D(2) +... 5d6p(1)D(2)), (... 5d(2) P-3(2)) and... (6s6d D-1(2)). Comparisons are made with existing theoretical results calculated in the convergent close coupling formalism and the unitarized distorted wave approximation.