Kaley A. Walker

Pure rotational spectra of the van der Waals complexes Ne–CO, Kr–CO, and Xe–CO

The pure rotational spectra of the van der Waals dimers of Ne, Kr, and Xe with CO have been measured using a pulsed jet, cavity microwave Fourier transform spectrometer. All transitions measured were a-type R-branches, obeying selection rules ΔJ=+1, ΔKa=0, and ΔKc=+1. Spectra with Ka=0 were measured for 7 isotopomers of Ne–CO, 13 of Kr–CO, and 17 of Xe–CO. Transitions with Ka=1 were measured for 20Ne–12C16O and 84Kr–12C16O. Rotational constants and centrifugal distortion constants have been determined for all species, as well as the 17O quadrupole coupling constants χaa for 84Kr–13C17O and 20Ne–13C17O. Effective structural parameters have been calculated from the rotational constants. Results derived from the 17O quadrupole coupling constants and centrifugal distortion constants indicate that Ne–CO is considerably more flexible than Ar–CO, Kr–CO, or Xe–CO. Failure to observe hyperfine structure due to the 21Ne, 83Kr, and 131Xe nuclei is discussed in terms of the weak rare gas–CO bonding. Comparisons have ...

Nuclear hyperfine interactions in the microwave spectrum of aluminium isocyanide

Abstract The pure rotational spectrum of AINC has been measured between 11.9 and 24.0 GHz using a pulsed jet Fourier transform microwave spectrometer. The molecule was produced using a laser ablation source, in which the ablated Al metal reacted with cyanogen present in the Ar backing gas of the jet. Hyperfine structure due to both the 27 Al and 14 N nuclei has been observed. Nuclear quadrupole coupling constants and nuclear spin-rotation constants have been determined for both nuclei along with an Al N nuclear spin-spin coupling constant. The electronic structure of AINC has been investigated by estimating the degree of sp -hybridisation of the Al and N bonding orbitals. Comparisons have been made to similar linear metal isocyanide and aluminium halide species.

The pure rotational spectrum of yttrium monobromide

The pure rotational spectrum of the X 1Σ+ ground electronic state of yttrium monobromide has been measured. This is the first high-resolution spectrum recorded for this molecule. Transitions in the ground and first excited vibrational states have been measured for both the Y79Br and Y81Br isotopomers. Equilibrium rotational parameters have been determined and an equilibrium bond distance has been calculated. Vibrational parameters have been estimated. Hyperfine structure due to the bromine nuclei has been observed and nuclear quadrupole and nuclear spin–rotation constants have been determined. These parameters have been used to investigate the ionic character of the Y–Br bond and comparisons have been made to several alkali and alkaline earth metal bromide species.

Laboratory microwave spectroscopy of aluminium cyanide

Abstract The pure rotational spectrum of aluminium cyanide (AlCN) between 10 and 21 GHz has been investigated by Fourier transform microwave spectroscopy. Molecular samples were produced by reacting ablated Al metal with cyanogen present in an Ar supersonic jet. Rotational and centrifugal distortion constants and 27 Al and 14 N nuclear quadrupole coupling constants and nuclear spin–rotation constants have been determined for the main isotopomer, 27 Al 12 C 14 N. The spectrum of AlCN was found to be much weaker than that of AlNC thus confirming that AlCN is the less stable of the two isomers.

Investigation of the pure rotational spectrum of magnesium monobromide by Fourier transform microwave spectroscopy

The pure rotational spectrum of the free radical MgBr has been measured in its 2Σ+ ground electronic state by Fourier transform microwave spectroscopy. Transitions have been observed for both 24Mg79Br and 24Mg81Br in the v=0 and v=1 vibrational states. Rotational and centrifugal distortion constants have been determined for each isotopomer in each vibrational state. Equilibrium rotational constants have been calculated and an accurate equilibrium bond length has been determined. Spin-rotation constants, for both the unpaired electron and the bromine nuclei, have been calculated along with magnetic and nuclear quadrupole hyperfine constants for the bromine nuclei. From these constants, the electronic structure of MgBr has been investigated and comparisons have been made to similar compounds. The unpaired electron spin density on the bromine nucleus has been found to be very small, suggesting that this is a very ionic compound. However, the Mg–Br bond has been found to have more covalent character than the ...