Near infrared absorption spectrum of perfluoro-t-butanol/acetonitrile complexes at low temperatures: Fermi resonances and simultaneous transitions
✍ Scribed by André Burneau
- Book ID
- 103907313
- Publisher
- Elsevier Science
- Year
- 1989
- Tongue
- English
- Weight
- 842 KB
- Volume
- 45
- Category
- Article
- ISSN
- 1386-1425
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✦ Synopsis
interactions between perfluoro-t-butanol (PFTB) and acetonitrile-d, (AN) in a mixture of freons are studied between 298 and 88 K in Iiquid or vitreous states, In the conditions of the experiment, a mean 1:2 stoichiometry [PFTB..(AN),] is inferred from previous matrix measurements. A vOH shift of about 16Ocm-1 is observed in this temperature range: it is mainly ascribed to solvent effects on the complex. In fact, the dvon/dTcoefficient increases at low temperature on account of specific solvation of the complex by the freon Br atoms. The vou + rou combination wavenumber is little dependent on the state of PFTB, near 3900 cm-'. A comparatively strong simultaneous transition involving the PFTB van mode and a vC=N mode of neighbouring AN molecules is observed. Weaker bands could also be explained by such transitions involving a combination level of PFTB and a vCEN vibration. Strong Fermi resonances are displayed in the 2V," region when the van band is located around 31OOcm-', either in pure AN or in freons at low temperature. The levels interacting with 2vo,, are ternary combinations and quaternary overtones mainly involving the COH bend and the CO stretch. These resonances are favoured by a strong increase of the OH stretching vibration anha~oni~ity.