Low-frequency Raman scattering in As₂S₃glass former around the liquid–glass transition

Abstract

Low-frequency light scattering spectra of As2S3 glass former have been investigated over a temperature range of 300–712 K. Using the model of a damped oscillator, the parameters of the intensities of the boson peak and of the fast relaxation as well as the boson peak position and the relaxational time are extracted as a function of temperature. The temperature increase of the fast relaxation becomes more sharp above Tg and stabilizes at T = 600 K. By analogy with other glass formers it is suggested that the critical temperature Tc within the framework of the mode-coupling theory should be near 600 K for As2S3. It was found that the damping parameter at Tc is the same for As2S3 and B2O3; an explanation of this coincidence is suggested. The boson peak is found to be present up to 712 K with almost the same strength as at low temperatures.

Annealing-induced formation of Sn2P2S6 crystallites in As2S3-based glass matrix

“…4. The extensively studied Raman spectrum of glassy As 2 S 3 [28][29][30][31][32][33][34][35][36][37] is known to be dominated by a broad band in the range of 300−400 cm −1 , which is related to symmetric stretching vibrational modes of AsS 3/2 pyramids (AsS 3 pyramids are linked together by As-S-As bonds) [31,33]. A weak band at 490 cm −1 is attributed to S-S stretching vibrations in S 8 rings indicating the presence of excessive sulphur [33].…”

Intermolecular vibrations and fast relaxations in supercooled ionic liquids

“…Several investigations of fast dynamics in glass-forming liquids by low-frequency Raman spectroscopy indicated a signature of T c as the temperature at which I QES reaches a plateu and becomes temperature independent. [110][111][112] These analyses have been carried out mainly by using the coupling model for the relaxational and vibrational contributions of Raman spectra (not to be confused with the MCT theory for glass formation), in which I QES is giving by the strength parameter δ 2 (T) of coupling between relaxations and boson peak vibrations. [57][58][59][110][111][112] It is worth stressing that δ 2 (T)…”

“…7 is another linear regime for I QES (T) above this temperature, rather than I QES (T) reaching a plateu at T > T c . [110][111][112] Nevertheless, three characteristic temperatures, T o , T g , and T c , can be discernible and distinct regimes of I QES are probed by low-frequency Raman spectroscopy of the ionic liquid [hmIm][Tf 2 N].…”

Raman scattering evidence of instantaneous nanoscale order in liquids and plastic crystals

“…Low-frequency Raman scattering spectra of the As 2 S 3 glass-former were studied experimentally over a temperature range of 300-712 K in [14]. The highest temperatures studied significantly exceed T g ~ 460 K and T m ~ 580 K of the material.…”

“…Raman spectra of As 2 S 3 at T = 293 K (solid curve), 498 K (dotted curve), and 693 K (dashed curve). Data from [14]. b) Temperature dependence of integral intensity of the boson peak in the As 2 S 3 glass-former (from [14]).…”