UBC Theses and Dissertations
Xenon-copper chemical bonding : Fourier transform microwave spectroscopy of XeCuX (X = F, C1) Michaud, Julie M.
The rotational spectra of seven isotopomers of XeCuF and eight isotopomers of XeCuCl have been measured in the range of 7-22 GHz using a pulsed jet cavity Fourier transform microwave spectrometer. The molecules were prepared by laser ablation of a Cu metal rod with a pulsed Nd:YAG laser at 1064 nm and allowing the plasma to react with appropriate precursors (Xe and SF6 or CI2) entrained in a carrier gas of Ar. Rotational constants, centrifugal distortion constants, internuclear distances, vibration frequencies, and Xe, Cu and CI hyperfme coupling constants have been evaluated. The Xe-Cu bonds are short and the molecules are rigid. The 1 3 1Xe nuclear quadrupole coupling constants in both XeCuF and XeCuCl are large (-87.8 and -81.4 MHz, respectively). The Cu nuclear quadrupole coupling constants differ radically from those of uncomplexed CuF and CuCl molecules. Ab initio calculations have supported the experimental results with short NgM bonds and rigid molecules. Mulliken populations and MOLDEN plots have also been calculated and both are consistent with strong interactions between the noble gas and the noble metal. The local energy densities were calculated to be negative and indicate the presence of a covalent XeCu bond. Both experimental and theoretical results are consistent with those reported earlier for other noble gas - noble metal halide molecules. The evidence is convincing for chemical bonding present between the noble gas and the noble metal in all NgMX molecules.
Item Citations and Data