Absolute cross sections for electron-impact excitation of the 3d(2) F-3 -> 3d4p D-3, F-3 transitions in Ti2+

The absolute cross sections for the 3d(2) F-3 --> 3d4p D-3, F-3 excitation of Ti2+ ions at electron energies close to threshold (9-10 eV) were measured using the merged electron-ion beams energy-loss technique. The value of the cross-section step for the sum of the 13 allowed transitions to D-3 and F-3 levels, separated in energy by less than 0.1 eV, is found to be (0.84+/-0.18) x 10(-16) cm(2). Results from a set of first-order distorted-wave calculations range from 0.53x10(-16) cm(2) to 1.63x10(-16) cm(2).