High pressure Raman study of intermolecular interactions and Fermi resonance in liquid ethylene carbonate

Abstract

The Raman band of the ring vibration (ν5) and the Fermi resonance between the carbonyl stretching (ν2) and the first overtone of the ring breathing vibration (2ν7) have been studied in liquid ethylene carbonate in the pressure range between 1 and 3000 bar and at temperatures from 40 to 160 °C. The relative changes of the transition dipole moments of both bands in resonance are estimated from the measurements of their intensity ratios. The knowledge of these parameters enables a comparison of the experimental frequency noncoincidence effect between isotropic and anisotropic components of the bands and the theory based on strong dipole moment coupling. The noncoincidence effect for the ν5 vibration are also explained in terms of this theory. The pressure induced frequency shifts of the bands are interpreted qualitatively by the permanent dipole–dipole coupling model.

Li + solvation in ethylene carbonate–propylene carbonate concentrated solutions: A comprehensive model

“…6͒ that no special effect appears in the intensity distribution among the two CϭO bands at 1770 and 1790 cm Ϫ1 , which are known to be sensitive to the external conditions of temperature, pressure and presence of polar molecules. 26 Similar results were obtained in Ref. 17.…”

“…25,26 Only for pure solvent and low electrolyte concentration (Nϭ0.069) the two components are well separated, while for any other concentration the components become broader and changes of spectral parameters are hard to be appreciated. This fact seems to indicate a rather continuous distribution of the interaction energy affecting the carbonyl bond, in a similar manner to the electrolyte-induced broadening of the ring bending mode 8 which involves the CϭO group.…”

Effect of carbonates fluorination on the properties of LiTFSI-based electrolytes for Li-ion batteries

“…The band, corresponding to the bulk solvent, arises at 1748 cm À1 , while the second band, appearing at lower wavenumbers (1715 cm À1 ), characterizes the coordinated solvents. With respect to the cyclic carbonate derivatives, the carbonyl vibration bands were not exploited in literature due to a Fermi resonance phenomenon [34]. Therefore, the ring-breathing mode in the range of 880-940 cm À1 was chosen for analysis, since also for this band a shoulder arises (at lower frequencies), which corresponds to coordinated molecules.…”

Changes in spectral features with varying mole fractions of anisaldehyde in binary mixtures

“…The observed higher wavenumber component (1705 cm 1 ) is assigned to the free (C O) and the lower wavenumber component (1684 cm 1 ) is due to the hydrogen-bonded (C O). 25 In 2-propanol, there is the formation of a hydrogen bond between the carbonyl oxygen (the lone pair electron) of 4MeOBz and the hydroxyl proton in 2propanol. 3), whereas in acetonitrile and benzene, the peak positions are upshifted with decreasing concentrations of 4MeOBz.…”