Vibrational spectroscopy of 1,1-difluorocyclopropane-d0, -d2, and -d4: the equilibrium structure of difluorocyclopropane.
J Phys Chem A
; 111(13): 2498-506, 2007 Apr 05.
Article
em En
| MEDLINE
| ID: mdl-17388345
ABSTRACT
IR and Raman spectra are reported for 1,1-difluorocyclopropane-d0, -d2, and -d4, and complete assignments of vibrational fundamentals are given for these species. These assignments are consistent with predictions of frequencies, intensities, and Raman depolarization ratios computed with the B3LYP/cc-pVTZ quantum chemical (QC) model. Ground state rotational constants for five 13C and deuterium isotopomers, obtained from published microwave spectra, were "corrected" into equilibrium rotational constants. The needed vibration-rotation interaction constants were computed with QC models after scaling the force constants. A semi-experimental equilibrium structure, fitted to the equilibrium moments of inertia, is rC1C = 1.470(1) A, rCC = 1.546(1) A, rCF = 1.343(1) A, rCH = 1.078(1) A, alphaFCF = 109.5(1), alphaFCC = 119.4(1) degrees, alphaHCH = 116.7(1) degrees, alphaC1CH = 117.4(1) degrees, and alphaCCH = 117.1(1) degrees. This structure agrees within the indicated uncertainties with the ab initio structure obtained from an extrapolated set of CCSD(T)/aug-cc-pVnZ calculations except for rCC = 1.548 A. The F2C-CH2 bonds are significantly shortened and strengthened; the H2C-CH2 bond is significantly lengthened and weakened.
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Base de dados:
MEDLINE
Idioma:
En
Ano de publicação:
2007
Tipo de documento:
Article