Nuclear hyperfine coupling interactions in the rotational spectra of the linear and bent isomers of HF-N2O

The rotational spectra of six isotopomers of the linear and bent isomers of HF-N2O have been collected in the 7-18 GHz region with a Fourier transform microwave spectrometer. The nuclear hyperfine structure in the spectra produced by HF spin-spin coupling interaction and nuclear quadrupole coupling interactions due to the D nucleus of DF and the N-14 nuclei of N2O have been resolved and analyzed. In the linear isomer, H in HF is bonded to the terminal N in N2O. The NF bond lengths are 2.9808(2) Angstrom for the HF-containing isotopomers and 2.9732(2) Angstrom for the DF-containing isotopomers. The zero point angles are 23.1degrees for HF and 3134 for N2O. The hyperfine constants suggest that the HF bond is lengthened by 0.0105 Angstrom upon complexation and that the electric field gradients of the two nitrogen nuclei in N2O are perturbed differently in the complex. In the bent isomer, the hydrogen bond is formed between HF and O in N2O. The intermolecular distances are 3.4942(2) Angstrom for the HF-containing isotopomers and 3.4436(2) Angstrom for the DF-containing isotopomers, with HF and N2O forming angles of 34 and 46, respectively, with the intermolecular axis. The nuclear quadrupole coupling constants of the two nitrogen nuclei do not indicate electric field gradient perturbation in this isomer. (C) 2003 Elsevier Science (USA). All rights reserved.