The excitation of Xe {6p} atoms in the nitrogen afterglow was studied using Xe {6p} → Xe {6s} emission. Xenon levels lying close to the N2 dissociation limit D0(N2) (6p[ 5 2 ]3, 6p[ 3 2 ]1 and 6p[ 3 2 ]2 are directly excited in the process of three-body recombination The population of the xenon levels 6p[ 1 2 ]1 and 6p[ 5 2 ]2 which lie deeper involves energy transfer from the excited nitrogen molecules, stabilized by vibrational relaxation. The population of the Xe {6p} levels shows termolecular kinetics with the following third-order rate constants (units, 10−35 cm6 molecule−2 s−1 at T = 293 K: k(6p[ 1 2 ]1) = 10.8, k(6p[ 5 2 ]2 = 3.7, k(6p[ 5 2 ]3) = 1.45, k(6p[ 3 2 ]1 = 0.147 and k(6p[ 3 2 ]2) = 0.072. In the temperature range 200–500 K the efficiency of Xe {6p} excitation is described by k(T) ≈ T 1 2 exp( − Eia/kT), which gives activation energies Eia for these levels of −261, −172, 0, 271 and 528 cm−1 respectively. The measured Eia values for the 6p[ 3 2 ]1 and 6p[ 3 2 ]2 levels, whose energies E(Xei) are higher than D0(N2), are close to their energies above D0(N2): E(Xei) − D0(N2). The quenching of Xe {6p} by He and N2 was also studied.
