Low Temperature Physics: 26, 727 (2000); https://doi.org/10.1063/1.1312400 (9 pages)
Физика Низких Температур: Том 26, Выпуск 9-10 (Сентябрь 2000), c. 981-991    ( к оглавлению , назад )

Infrared and EPR spectroscopic study of open-shell reactive intermediates: F + NH3 in solid argon

Eugenii Ya. Misochko, Ilya U. Goldschleger, and Alexander V. Akimov

Institute of Problems of Chemical Physics of the Russian Academy of Sciences 142432 Chernogolovka, Moscow district, Russia
E-mail: ilya@icp.ac.ru

Charles A. Wight

Department of Chemistry, University of Utah, Salt Lake City, Utah 84112, USA

Received February 1, 2000


Mobile F atoms react with NH3 molecules in an argon matrix at temperatures T=7√35 K. The open-shell NH2√HF complex was observed by EPR and infrared spectroscopies as the main product of this reaction. The hyperfine constants of the NH2√HF complex aN=1.20 mT, aH=2.40 mT, and aF=0.70 mT were determined from the EPR spectra of samples using NH3, 15NH3 and ND3 isotopomers. Prominent features of the infrared spectrum of NH2√HF are a strongly red-shifted HF stretching mode (Dn≈ - 720 cm-1 relative to that for isolated HF) and strong absorptions at 791 and 798 cm-1 attributed to HF librational modes in the complex. Quantum chemistry calculations reveal that the hydrogen-bonded NH2 √HF complex has a planar C2n structure and a binding energy of 51 kJ/mol. Calculated hyperfine constants and vibrational frequencies of the complex are in good agreement with those observed in the EPR and IR experiments.

82.30.Cf - Atom and radical reactions; chain reactions; molecule-molecule reactions