Low frequency vibrational spectroscopy of highly viscous and highly polar liquids

✍ Scribed by T.S. Perova; J.K. Vij

• Book ID: 104303806
• Publisher: Elsevier Science
• Year: 1996
• Tongue: English
• Weight: 801 KB
• Volume: 69
• Category: Article
• ISSN: 0167-7322
• DOI: 10.1016/s0167-7322(96)90002-1

✦ Synopsis

The far infrared (FIR) spectra of glycerol and triacetin has been studied and the lowfrequency depolarized Raman spectra of glycerol, triacetin and a number of liquids of the ketone series have also been reported at temperatures of -10 oC, 20 oC and 55 OC. The spectra of glycerol and triacetin shows broad low frequency peaks which at certain temperatures can be split in more than one peak. It has been shown that for most liquids studied here the two spectra (FIR and Raman), in the appropriate representation, are in agreement with each other. In the literature several models including the itinerant oscillator are able to satisfactorily explain the spectral features of the PIR absorption, however theory needs to be extended to explain the spectral features of the low-frequency Raman spectrum and its comparison with the FIR spectra. We tentatively explain a correlation between the peak frequency and the compressibility of these liquids and suggest that perhaps Szigeti's model for the ionic solids is extendable to the molecular liquids where the lattice vibrations may correspond to the collective rotatory oscillations of molecular dipoles.