Optical emission in the dissociation of ammonia by low energy He+ ions
Institute of Experimental Physics, Faculty of Mathematics, Physics, and Informatics, University of Gdansk, ul. Wita Stwosza 57, 80-308 Gdansk, Poland
Received: 22 November 2016
Received in final form: 19 January 2017
Published online: 28 March 2017
Molecular bands associated with the ND(A-X), ND(c-a), ND+(B-X), and ND+(C-X) transitions, as well as atomic lines of Balmer series and several He and He+ lines, were observed in the collisions of He+ with ND3 gas target at energies between 17 eV and 833 eV in the center-of-mass frame. Absolute luminescence cross sections, excitation functions, and the ND(c-a)/ND(A-X) branching ratios (BR) were determined. The sum of all luminescence cross sections in the 200–600 nm spectral window is below 1 × 10-20 m2 at 833 eV. The ND(c-a)/ND(A-X) luminescence BR increases with collision energy from BR = 0.20 at 20 eV to BR = 0.30 at 150 eV and up to 833 eV. Computer simulations of the spectra were used to estimate rotational and vibrational temperatures of the products. The population distributions of rotational and vibrational states of ND∗(A, c) do not vary appreciably with collision energy.
Key words: Molecular Physics and Chemical Physics
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