Nitrogen quadrupole hyperfine splitting in the microwave spectrum of dinitrogen trioxide

Abstract

Nitrogen quadrupole splittings in the microwave spectra of N₂O₃, O¹⁵NNO₂ and ON¹⁵NO₂ have been examined. Analysis of splittings due to single and double nitrogen coupling has yielded coupling constants at both nuclei; accurate values have been obtained for _χaa(NO₂)=–2.0 ± 0.1 and _χaa(NO)=–1.9 ± 0.1 MHz respectively. The coupling constants have been interpreted, using a Townes-Dailey approach, in terms of the coupling found in nitric oxide and nitrogen dioxide perturbed by the weak N—N bond. This description, while predicting a moderately large value for _χaa at the nitrosyl nitrogen, satisfactorily accounts for the unusual structure and the value of the dipole moment in N₂O₃.