Hot-atom chemiluminescence: a beam study of the reaction N(4S)+H2→NH(A3Π)+H

A beam of N(4S) atoms at energies in the 10–1000 eV range was generated by near-resonant charge transfer of N+(3P) ions with krypton atoms. Chemiluminescence was observed upon collisions of the hyperthermal N atoms with H2 molecules at energies between 2.5 and 46 eVCM. The emission was spectroscopically identified as being due to the A3Π–X3Σ− transition of NH. At higher energies, some lines of atomic hydrogen were also observed. The dependence of the cross-section for NH(A) production as a function of collision energy was determined approximately. Possible contributions of a small N(2D) beam fraction were considered. The spectra (resolution 1.0 nm FWHM) indicate substantial rotational and vibrational excitation of the product, even at low energy.