We have recorded the cation spectra of three N-deuterium substituted 2,6-dimethylanilines by ionizing via the intermediate 0 degrees, CH3 torsion, and 6a(1) levels of each species in the S-1 state. Comparison of the present data with those of aniline isotopomers suggests that the S-1 <- S-0 electronic excitation and the D-0 <- S-1 transition of both molecular systems are alike. By comparing these results with those of aniline and o-methylaniline, we propose an additivity rule to predict the E-1 and IE. The observed active vibrations of these cations include the characteristic CH3 torsion and the in-plane ring vibrations. (C) 2012 Elsevier B.V. All rights reserved.