The reactions of N 2 (aЈ 1 ⌺ u Ϫ , vϭ0͒ with H 2 , CH 4 , and their isotopic variants were examined. N 2 (aЈ, vϭ0͒ was produced by energy transfer from N 2 (a 1 ⌸ g , vϭ0͒, while N 2 (a, vϭ0) was produced by two-photon excitation of ground state N 2 . The rate constant for the deactivation of N 2 (aЈ,vϭ0͒ can be determined by measuring the decay profiles of N 2 (a, vϭ0) under the conditions that equilibration between N 2 (a, vϭ0) and N 2 (aЈ, vϭ0) can be assumed. The detection of N 2 (a, vϭ0) was accomplished by a laser-induced fluorescence technique by utilizing the N 2 (bЈ 1 ⌺ u ϩ , vϭ7͒ state as an upper state. The rate constants for the quenching of N 2 (aЈ, v ϭ0͒ by N 2 , H 2 , D 2 , CH 4 , CH 2 D 2 , and CD 4 were determined to be ͑2.0Ϯ0.1͒ϫ10 Ϫ13 , ͑2.8Ϯ0.1͒ ϫ10 Ϫ11 , ͑1.7Ϯ0.1͒ϫ10 Ϫ11 , ͑2.9Ϯ0.2͒ϫ10 Ϫ10 , ͑2.4Ϯ0.3͒ϫ10 Ϫ10 , and ͑2.6Ϯ0.2͒ ϫ10 Ϫ10 cm 3 molecule Ϫ1 s Ϫ1 , respectively. H͑D͒ atoms were identified as reaction products by a two-photon laser-induced fluorescence technique. The yields for the production of H͑D͒ atoms from CH 4 and CD 4 were both determined to be 0.7Ϯ0.2 under the assumption that the only exit for H 2 ͑D 2 ) is the production of two H͑D͒ atoms. No preferential production of H or D atoms was observed in the reaction with CH 2 D 2 , suggesting that the reaction proceeds via bound intermediate complexes.
