On the extent of polymerization of liquid sulfur at very high temperatures

Andrikopoulos, Konstantinos S.; Kalampounias, Angelos G.; Yannopoulos, Spyros N.

doi:10.1063/1.2185097

Cited by 6 publications

(3 citation statements)

References 13 publications

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“…Raman spectroscopy has played an essential role in providing a means for a reliable, in situ estimation of the polymer content up to very high temperatures [22,31]. In this context, a long standing issue was tackled paving the way for investigations of the λ-transition of sulfur under the influence of various other conditions, as is discussed below.…”

Section: Liquid Sulfurmentioning

confidence: 99%

“…The dashed lines denote the positions of the bands assigned to the monomer (S 8 ) and polymer (S n ) species. (b) Temperature dependence of the extent of polymerization 𝜙(𝑇) represented by the intensity ratio 𝐼 𝑆 𝑛 /(𝐼 𝑆 𝑛 + 𝐼 𝑆 8 ) where 𝐼 𝑆 𝑛 and 𝐼 𝑆 8 denote the integrated intensities of the symmetric bond-stretching vibrational mode (S-S) corresponding to polymeric and S 8 ring species, respectively[22,31]. Crossed squares: data from other methods[32].…”

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confidence: 99%

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Structure and photo-induced effects in elemental chalcogens: a review on Raman scattering

Yannopoulos

2020

J Mater Sci: Mater Electron

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Much progress has been made over a long period, spanning more than a century, in understanding the atomic arrangement on various length scales of non-crystalline chalcogens and their transitions upon certain external stimuli. However, it is broadly admitted that there are still several unsettled issues that call for proper rationalization. The current review presents an assessment of Raman scattering studies of non-crystalline phases of elemental chalcogens and their mixtures. First, a few remarks on the analysis of Raman data, related to polarization details and spectra reduction are presented. The effect of temperature, pressure and irradiation on the structure of chalcogens is reviewed in detail. As only selenium can form a stable glass at ambient conditions, the interest on sulfur and tellurium has been placed in the melt and the amorphous phase, respectively, whereas reference is also made to the sporadic structural studies of glassy sulfur at low temperatures. It is shown how Raman scattering can be exploited to explore unique phenomena emerging in the liquid state of sulfur, offering valuable information on the details of λ−transition including various thermodynamic-related properties. The subtle nature of this transition in selenium is also discussed. Tellurium is not only impossible to be prepared in the bulk glassy state, but also forms a very liable to crystallization amorphous film. Therefore, the emphasis is placed on light-induced nanostructuring and effects related to photo-amorphization and photo-oxidation. 2 IntroductionNon-crystalline chalcogenides, either as bulk glasses or amorphous films, have attracted extensive interest since their discovery, not only from the viewpoint of fundamental science but in addition owing to the technological potential that these materials exhibit over diverse sectors of active and passive applications [1,2]. Structure on the atomic scale is the decisive factor that determines macroscopic properties and ultimately function of the material. In addition, photoinduced effects, a hallmark of non-crystalline chalcogenides, depend on composition since structural arrangement must be suitable to allow photoinduced transformations on various length scales [3,4]. Understanding structure will not only allow identifying why a material behaves macroscopically in a certain manner, but will make feasible to establish structure-property relations. The latter are central to progress from serendipitous discoveries of functional materials to a rational design of materials with tailored properties. Disorder abolishes all the amenities accompanying the crystal periodicity, which render the role of structure-property relationships indispensable to disordered media.Resolving structure in the amorphous state is per se a formidable task. This is true even for simple systems, e.g. monoatomic chalcogens, let alone for multicomponent materials. Research for applications in non-crystalline chalcogenides has since the beginning of their discovery moved to studies of multicomponent systems, i.e....

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Section: Liquid Sulfurmentioning

confidence: 99%

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confidence: 99%

Structure and photo-induced effects in elemental chalcogens: a review on Raman scattering

Yannopoulos

2020

J Mater Sci: Mater Electron

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“…With a further increase of temperature, the viscosity starts to drop until the boiling point of sulfur is reached at T = 718 K. This large increase of the viscosity and the underlying structural evolution during the polymerization transition is still under debate; see, for example, Refs. [11][12][13][14][15][16]. Also the diffusion coefficient [17] mirrors that transition as well as light absorption properties [18] and heat capacity [19].…”

Section: Introductionmentioning

confidence: 97%

Collective dynamics of liquid sulfur scrutinized over three decades in frequency

Demmel

Jiménez‐Ruiz

2022

Phys. Rev. E

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The glassy and supercooled state of elemental sulfur: Vibrational modes, structure metastability, and polymer content

Andrikopoulos

Kalampounias

Falagara

et al. 2013

The Journal of Chemical Physics

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We report a detailed investigation of vibrational modes, structure, and dynamics of elemental sulfur in the glassy and the supercooled state, using Raman scattering and ab initio calculations. Polarized Raman spectra are recorded--for sulfur quenched from 473 K--over a broad temperature range from 93 K to 273 K where the supercooled liquid crystallized. The temperature induced shifts of the majority of the vibrational modes are determined and compared with the corresponding ones of crystalline sulfur. Analysis of the reduced isotropic spectra showed that the structure of the quenched product is composed of eight member rings (S8) and polymeric chains (Sμ) with a relative fraction comparable to that of the parent liquid at 473 K. Low temperature spectra, where spectral line broadening due to thermal effects is limited, revealed that two different polymeric species are present in the glass with distinct vibrational frequencies. Their interpretation was assisted by ab initio calculations used to simulate the vibrational frequencies of polymeric chains S(8k) (k = 1, ..., 7). Theoretical results exhibit an increasing breathing mode frequency for sulfur chains up to k = 2, although it remains constant beyond the above value. The polymeric content is metastable; heating the glass above its glass transition temperature, T(g), destabilizes the chains and drives them back to the more thermodynamically stable rings. This bond interchange mechanism provides the structural origin of a secondary relaxation process in supercooled sulfur reported long ago, which has been also considered as a complication in the correct fragility estimation of this material. Finally, the Boson peak of the glass was found to exhibit strong temperature dependence even at temperatures below T(g).

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On the extent of polymerization of liquid sulfur at very high temperatures

Cited by 6 publications

References 13 publications

Structure and photo-induced effects in elemental chalcogens: a review on Raman scattering

Structure and photo-induced effects in elemental chalcogens: a review on Raman scattering

Collective dynamics of liquid sulfur scrutinized over three decades in frequency

The glassy and supercooled state of elemental sulfur: Vibrational modes, structure metastability, and polymer content

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