Chemiluminescent reactions of C( 3 P) atoms and C + ( 2 P) ions with NH 3 were investigated in the 12-1000 eV Lab (7-586 eV CM ) energy range, using a beam/gas arrangement. The fast carbon atoms were generated from C + ( 2 P) ions by near-resonant charge transfer with CCl 4 . The reaction products NH(A 3 Π), CN(B 2 Σ + ), and CH(A 2 ∆) were studied by means of the NH(A-X), CN(B-X), and CH(A-X) emission spectra at 1.4 and 0.35 nm fwhm resolution. Besides, traces of NH(c 1 Πa 1 ∆), CH(B 2 Σ --X 2 Π), and Balmer line emission were also observed. The reactions were classified as follows: (a) CH(A) is formed by exchange reactions, which are assisted by a hard-sphere-collision mechanism at high energies to moderate the kinetic energy; (b) NH(A) and NH(c) originate at low energies from substitution reactions, and NH(A) also results from collisional dissociation at high energies; (c) CN(B) is formed (only at low energies) via a long-lived [C-NH 3 ] + complex. Detailed evidence for these assignments came from the observed spectra, which were analyzed by means of a computer simulation, as well as from measurements of the energy-dependent relative cross sections.
Proton transfer between ions of the cyclic peptide valinomycin (relative molecular mass 1110.6) and ammonia molecules has been studied over a range of ion energies from 50 eV to 8 keV. Valinomycin ions were produced by field desorption. Collisions of valinomycin ions with ammonia molecules at controlled energies were carried out using an ion-optical lens system situated in the source region of a large research mass spectrometer. The maximum cross-section for proton transfer occurred when the valinomycin ion possessed 1500 e
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