Boson peak in the room-temperature molten salt tetra(n-butyl)ammonium croconate -: art. no. 104303

Low-frequency (5-200 cm(-1)) Raman spectra of the room-temperature molten salt, tetra(n-butyl)ammonium croconate (TBCR), [(n-C4H9)(4)N](2)C5O5. 4H(2)O, are reported. TBCR is a very viscous liquid with glass transition temperature T-g=20 degreesC. According to the temperature dependence of the viscosity, TBCR has been classified as a fragile glass-forming liquid. Raman spectra of TBCR have been obtained from 360 K down to a deep supercooled state at 77 K. The boson peak is observed in the Raman spectra as long as the system is cooled below T-g. The spectra are discussed in terms of proposed theories for depolarized light scattering in glass-forming liquids.