caa a22 4500 378913662 CHVBK 20180305123548.0 cr unu---uuuuu 161128e20040401xx s 000 0 eng 10.1524/zpch.218.4.439.29201 doi (NATIONALLICENCE)gruyter-10.1524/zpch.218.4.439.29201 The Four Isotopomer Reactions of NH(a) and ND(a) with NH3(X̃) and ND3(X̃) [Elektronische Daten] [L. Adam, W. Hack, Matthias Olzmann] The reactions NH(a) + NH3(X̃) → products (1) ND(a) + NH3(X̃) → products (2) NH(a) + ND3(X̃) → products (3) ND(a) + ND3(X̃) → products (4) were studied in a quasi-static reaction cell at room temperature and pressures of 10 and 20mbar with He as the main carrier gas. The electronically excited reactants NH(a) and ND(a) were generated by laser-flash photolysis of HN3 and DN3, respectively, at λ = 308nm and detected by laser-induced fluorescence (LIF). Also the ground state species NH(X) and ND(X) as products were detected by LIF. From the measured concentration-time profiles of NH(a) and ND(a) under pseudo-first order conditions, the following rate constants were obtained: NH(a) + NH3(X̃) → products (1) ND(a) + NH3(X̃) → products (2) NH(a) + ND3(X̃) → products (3) ND(a) + ND3(X̃) → products (4) k1 = (9.1 ± 0.9) × 1013 cm3mol−1s−1 k2 = (9.6 ± 1.0) × 1013 cm3mol−1s−1 k3 = (8.0 ± 1.0) × 1013 cm3mol−1s−1 k4 = (7.2 ± 0.8) × 1013 cm3mol−1s−1. The major products are the corresponding NHiD2 − i(X̃) radicals (i = 0, 1, 2), whereas quenching processes such as NH(a) + ND3 → NH(X) + ND3 are of minor importance (1%). The isotope exchange NH(a) + ND3 → ND(X) + NHD2 is negligible, and the corresponding channel on the singlet surface NH(a) + ND3(X~) → ND(a) + NHD2(X̃) contributes with 1% to the overall NH(a) depletion in that reaction. The experimental findings are discussed in terms of a chemical activation mechanism by means of statistical rate theory. © 2004 Oldenbourg Wissenschaftsverlag GmbH Thermodynamics & statistical physics nationallicence Laboratory techniques, experiments nationallicence Physical chemistry nationallicence Adam L. aut Hack W. aut Olzmann Matthias aut Zeitschrift für Physikalische Chemie/International journal of research in physical chemistry and chemical physics Oldenbourg Wissenschaftsverlag GmbH 218/4/2004(2004-04-01), 439-456 0942-9352 218:4/2004<439 2004 218 zpch https://doi.org/10.1524/zpch.218.4.439.29201 text/html Onlinezugriff via DOI 1 research article jats NATIONALLICENCE 856 40 https://doi.org/10.1524/zpch.218.4.439.29201 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Adam L. aut NATIONALLICENCE 700 1- Hack W. aut NATIONALLICENCE 700 1- Olzmann Matthias aut NATIONALLICENCE 773 0- Zeitschrift für Physikalische Chemie/International journal of research in physical chemistry and chemical physics Oldenbourg Wissenschaftsverlag GmbH 218/4/2004(2004-04-01), 439-456 0942-9352 218:4/2004<439 2004 218 zpch CC0 http://creativecommons.org/publicdomain/zero/1.0 nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-gruyter