The outcome of neutral and photoionized N͑CH 3 ͒ 2 primary products of trimethylamine photodissociation at 193 nm is determined by combining photoionization detection with supporting G3 theoretical calculations. N͑CH 3 ͒ 2 primary products with very little internal energy show an experimentally observed ionization onset of 9.1Ϯ0.2 eV, but do not appear at the parent ion (m/eϭ44). Instead, the parent ion is unstable and easily fragments to m/eϭ42, where the signal is observed. N͑CH 3 ͒ 2

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... with higher internal energies undergo H-atom loss from the neutral to give CH 2 NCH 3 , which has an observed ionization onset at parent (m/eϭ43) of Ͻ9.3 eV. At slightly higher ionization energies, these secondary products also appear at m/eϭ42 ͑where their appearance energy is roughly 9.8-9.9 eV, uncorrected for internal energy͒. Finally, N͑CH 3 ͒ 2 radicals with the highest internal energy in this study appear to undergo H 2 loss as neutrals, giving rise to a species whose parent ion has m/eϭ42. The ionization onset of this species at m/eϭ42 is found to be in the range of 9.5-9.6 eV.