Articles you may be interested inLowfrequency nuclear magnetic resonance and nuclear quadrupole resonance spectrometer based on a dc superconducting quantum interference device Rev. Sci. Instrum. 62, 1453 (1991); 10.1063/1.1142466The Jahn-Teller effect in the photoelectron spectrum of iron pentacarbonyl

A normal-coordinate treatment for the series CH2XY halosubstituted methanes (X = F or I; Y = Cl or Br) was carried out with a 709 digital computer and a perturbation program supplied by Schachtschneider of the Shell Development Company. A reasonable set of potential constants was obtained for each molecule that reproduced exactly the observed fundamentals. Trends that were noticed among the potential constants of the obtained sets were demonstrated and discussed. The potential-energy distributions for each molecule were calculated. The effect of the redundancy on the quadratic potential constants as well as an estimate of the first-order potential energy constants were obtained according to the method of Crawford and Overend. In the present work, the assignments of the ν3 and ν8 fundamentals of the two iodinated compounds, as given by Pitzer and Gelles, were interchanged and the argument for this change was given. A new value for the unperturbed ν5 of the fluorobromomethane, which is undergoing a Fermi resonance with 2ν6, was adopted. This new value, higher than that adopted by Pitzer and Gelles, is backed by the results of the normal-coordinate treatment. Mean-square amplitudes of vibration for bonded and nonbonded atoms for the four molecules, as well as the Coriolis coupling coefficients were calculated. With the adopted values of the fundamentals, the usual ideal-gas thermodynamic properties were calculated for the four compounds based on the latest values of the physical constants and the carbon−12 atomic mass scale.

Su ita ble ba nd of co mmon "a 'es have bee n tabulated and remeasured wh ereve r I\ ecessary from 2 to 16 microns to obtain a n accuracy of a bou t 0.03 cm-L t hroug hou t the re"ion an d to provide good calibrating poin t at fr eq uent intervals. So me 600 rotation-vibration l in es ar e illustrated in 20 spectrograms a nd wave numbers are listed in co mpa nion tables wi t h considerable in te rco mpa rison with worthy d ata obtain ed in other labo rato ri es. The a bsol'potion bands were remeasLIl'ed o r calibrated by usin g eith er a prec isely graduated gratin g circle or stal\da rd ato mi c lin es with t he frin ge system form ed by a F a b ry-P erot interf erometer . Characte ri stic featnres of t he individual ba nds are d iscu ssed bri efly and refere nces to other publi cations are g iv en . Th e su bstances used fo r calibration in clud e H 2 0, CO" CO, H Cl, HBr, N H 3, C2H2, CH., N2 0, a nd polysty rene film .

The infrared and Raman spectra of vinylene carbonate have been observed from 50 to 4000 cm−1 and most of the fundamental modes of vibration have been assigned. The B2 ring-puckering vibration is at 258 cm−1 in the liquid, in good agreement with the results of microwave intensity measurements. A short C–O bond length, on the order of 1.15–1.17 Å, is indicated by the high frequency of the carbonyl stretching frequency.

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