Rotational spectrum and molecular properties of the dinitrogen–chlorine monofluoride complex

Abstract

The ground-state rotational spectra of the three isotopomers 14N2⋯35ClF, 15N2⋯35ClF and 15N2⋯37ClF of a complex formed by dinitrogen and chlorine monofluoride have been observed with a pulsed-nozzle, Fourier-transform microwave spectrometer. The spectroscopic constants B0, DJ, χaa(A)(A =14Ni, 14No or Cl) and Mbb(Cl) are reported. The complex is shown to have a linear (or nearly linear) arrangement NoNi⋯ClF of the nuclei in the equilibrium conformation with r(Ni⋯Cl)= 2.920(2)A. The intermolecular stretching force constant, kσ= 5.00(5) N m–1, is implied by the centrifugal distortion constant DJ. Interpretation of the nuclear quadrupole coupling constants χaa(A) leads to the oscillation angles θav= cos–1〈cos2θ〉1/2= 17.8(5)° and ϕav= cos–1〈cos2θ〉1/2= 10(3)° for the N2 and ClF subunits, respectively. Additionally, the diffence χaa(Ni)–χaa(No) leads, on the basis of a simple model, to the conclusion that the polarisation of N2 attending complex formation is equivalent to the transfer of a fraction δ≈ 0.02 of an electronic charge from No to Ni. A comparison of the properties of four related complexes N2⋯YF and OC⋯YF, where Y = Cl or H, is presented.