Nuclear Quadrupole Hyperfine Structures of the Rotational Transitions of the NH3–N2 van der Waals Dimer.
Wendy C. Topic, Yunjie Xu and Wolfgang Jäger
Department of Chemistry, University of Alberta, Edmonton AB T6G 2G2, Canada
An initial study of the K = 0 ortho-ortho R(0) to R(3) transitions of NH3–N2, measured with a molecular beam electric resonance spectrometer, was previously reported. The hyperfine structures of these transitions were partially resolved, but not assigned. More recently, six series of NH3–N2 rotational transitions were observed and assigned in the millimetre-wave region for R(11) to R(16), without resolving the hyperfine structures. The lack of resolved and assigned hyperfine structure for this van der Waals complex was evidence that further studies in the microwave region were warranted. In addition, the identities of the previously assigned series of NH3–N2 would be further confirmed by investigations of the corresponding low J transitions. In the present study, the low J transitions of the six series were investigated, with particular emphasis on resolving and assigning the nuclear quadrupole hyperfine structures. The complex 14N hyperfine patterns were simplified by the use of 15NH3 enriched samples. Information about the structure and internal dynamics of the NH3–N2 van der Waals dimer will be presented in this paper.