Low-frequency vibrational excitations in the amorphous and crystalline states of triphenyl phosphite: A neutron and Raman scattering investigation

Raman spectroscopic and low-temperature calorimetric investigation of the low-energy vibrational dynamics of hen egg-white lysozyme

“…More precisely it has been found that the coupling coefficient follows a linear dependence described by the function A C + ∝ν ν ) ( , where A represents a no vanishing value assumed by C(ν) in the limit 0 → ν . This result is fully in agreement with the universal linear frequency behaviour of C(ν) found for a large number of different glasses near the Boson Peak frequency region [19,20,21] and puts into evidence, once again, the existence of a similarity between amorphous and biological systems.…”

On the origin of the boson peak

“…The Boson peak is a bump in the density of vibrational states (divided by the Debye density of states that is proportional to ω 2 ) at low temperature in the low ω region (Benassi et al 1996, Masciovecchio et al , Sette et al 1998, Engberg et al 1999, Fioretto et al 1999, Hédoux et al 2001. One of the remarkable and puzzling features of the Boson peak (that is explained by present approach) is that the sound velocity is linear in the region of the Boson peak, so that these low energy excitations do not appear at low momenta.…”

Size dependence of the Raman spectra in an amorphous–nanocrystalline mixed phase: the glacial state of triphenyl phosphite

“…The low-wavenumber shoulder was previously observed as corresponding to the envelope of the low-wavenumber phonons of the crystal. 7,9,12 Moreover, this shoulder was also observed as being one of the most characteristic Raman features of the glaciation. A neutron scattering investigation 12 of glassy and glacial states of TPP revealed that this shoulder is distinct from the boson peak that is unobservable in Raman spectra of the glassy TPP, as can be expected for a fragile molecular liquid.…”