Hot-atom chemiluminescence: a beam study of the N(4S)+CH4 system

Beams of fast N(4S) atoms (10–1000 eVlab) were generated by charge transfer of N+ ions with Kr atoms. NH(A–X) chemiluminescence (CL) resulting from N+CH4 collisions was spectrally resolved. The CL cross-section was determined relative to the N++CH4 CL reaction. It is only half as large, but has a very similar energy dependence. NH(A) formation up to unusually high collision energies (>200 eVCM) is explained by a `billiard ballʹ model. Spectra of CH (A2Δ, B2Σ−, C2Σ+) fragments were also observed at high energies. Computer simulations of the emission spectra from both the neutral and the ionic reaction yielded rovibrational populations. The differences are discussed.