Structural studies on fluid sulfur at high temperatures and high pressures: II. Molecular structure obtained by ab initio molecular dynamics simulations

Munejiri, Shuji; Shimojo, Fuyuki; Hoshino, Kozo; Inui, Masanori

doi:10.1016/j.jnoncrysol.2019.01.021

Cited by 5 publications

(6 citation statements)

References 21 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In a system of N particles in volume V and at temperature T , the correlation function g ( r ) can be written as Equation (). [ 101,102 ]

{normalg}^{(n)} (r_{1} ⋯, r_{n}) = \frac{V^{n} N!}{N^{n} false(N - n false)!} \cdot \frac{1}{Z_{N}} \int ⋯ \int e^{- k T U_{N}} d r_{n + 1} ⋯ d r_{N}

…”

Section: Density Functional Theorymentioning

confidence: 99%

“…Munejiri et al [ 102 ] investigated the structure of expanded fluid sulfur by AIMD simulations. As shown in Figure a, they found that with decreasing chain length at 1323 K, the bond length at the chain end decreased, whereas the bond length at the inside of the chain increased.…”

Section: Aimd Simulationsmentioning

confidence: 99%

“…Reproduced with permission. [ 102 ] Copyright 2019, Elsevier B.V. b) The pair correlation function g ( r ) at (i) different pressures; snapshots of the simulation boxes at (ii) three pressures; (iii) and pressure dependence of the total electronic DOS. Reproduced with permission.…”

Section: Aimd Simulationsmentioning

confidence: 99%

See 2 more Smart Citations

Surface/Interface Structure and Chemistry of Lithium–Sulfur Batteries: From Density Functional Theory Calculations’ Perspective

Shen

Wang

et al. 2021

Adv Energy and Sustain Res

View full text Add to dashboard Cite

Nowadays, the rapid development of portable electronic products and low‐emission electric vehicles is putting forward higher requirements for energy‐storage systems. Lithium–sulfur (Li–S) batteries with an ultrahigh energy density (2500 Wh kg−1) are considered the most promising candidates for next‐generation rechargeable batteries. However, the low conductivity of sulfur, the shuttle effect of lithium polysulfide (LPS), and inadequate safety caused by lithium dendrite formation limit their practical applications. In the research of Li–S batteries, it is observed that the surface/interface structure and chemistry of sulfur host materials play significant roles in the performance of Li–S batteries. The reason is that the adsorption/conversion of LPS mainly occurs on the surface/interface of host materials. The functional hosts are used to prevent the polysulfide shuttle or catalyze Li–S conversion reactions (enhance the reaction kinetics), and density functional theory (DFT) is used to understand the mechanism of the interaction between host and polysulfides. Herein, the surface/interface structure and chemistry of sulfur host materials involving structural factors and adsorption/conversion mechanisms of LPS (based on DFT calculation) on the interface are demonstrated. Finally, the remaining challenges, such as the fundamental studies and commercialized applications, as well as the future research directions are discussed.

show abstract

“…In a system of N particles in volume V and at temperature T , the correlation function g ( r ) can be written as Equation (). [ 101,102 ]

{normalg}^{(n)} (r_{1} ⋯, r_{n}) = \frac{V^{n} N!}{N^{n} false(N - n false)!} \cdot \frac{1}{Z_{N}} \int ⋯ \int e^{- k T U_{N}} d r_{n + 1} ⋯ d r_{N}

…”

Section: Density Functional Theorymentioning

confidence: 99%

Section: Aimd Simulationsmentioning

confidence: 99%

See 1 more Smart Citation

Surface/Interface Structure and Chemistry of Lithium–Sulfur Batteries: From Density Functional Theory Calculations’ Perspective

Shen

Wang

et al. 2021

Adv Energy and Sustain Res

View full text Add to dashboard Cite

show abstract

“…They also carried out experiments at high temperatures and pressures up to the liquid-vapour critical point to elucidate the dynamics of the chain length evolution of sulphur. On the basis of the above experimental data [31] and XRD results [32] at high pressures and temperatures, Munejiri et al [33] carried out an ab initio molecular dynamics simulation to investigate the time evolution of the chain structure. They found differences in bond length in the chains and at the chain ends.…”

Section: Introductionmentioning

confidence: 99%

Collective dynamics of liquid sulphur across the polymerisation transition temperature probed by inelastic x-ray scattering

Hosokawa,

Katayama,

Tsutsui

et al. 2024

J. Phys.: Condens. Matter

View full text Add to dashboard Cite

Inelastic x-ray scattering (IXS) experiments on liquid sulphur were carried out below (140◦C) and above (180◦C) the polymerisation temperature Tλ of about 159◦C to investigate changes in the collective dynamics of this unique liquid, that exhibits a liquid‒liquid transition. As reported earlier, broad longitudinal acoustic excitation signals were observed at both temperatures, and only the width of the quasielastic peaks slightly decreased when the temperature crossed the transition temperature. A model analysis was performed using a generalised Langevin formalism with a memory function having one thermal and two viscoelastic decay channels with the help of simple sparse modelling, and large positive deviations from the hydrodynamic sound velocity by 51‒54% were observed. The fast viscoelastic relaxation time τµis close to the correlation times of intermolecular stretching and bending motions of local sulphur connections in both ring and chain structures, and is similar to those of other molecular liquids. The small contrasts in the IXS spectra across the λ transition result in large changes in only the slow viscoelastic decay time τα of the memory function. The τα value at 140◦C matches the mixed internal/external torsional modes of S8 molecules well, whereas that at 180◦C has no corresponding molecular motion mode. The kinematic viscosity values at thesmaller than the minimum values of macroscopic shear viscosity, in⃗dicating that largeQ 0 limit are much changes in relaxation dynamics are expected with Q in the GHz and MHz excitation regimes.

show abstract

“…Density functional theory (DFT) and other theoretical approaches have been used previously to elucidate the conformational and thermodynamic properties of S 8 rings. ,− Ab initio molecular dynamics simulations have also been carried out to study the S 8 -ring opening at elevated temperatures and pressures, − as well as upon electronic excitation. − However, in these early pioneering studies, the states involved in the excited-state dynamics were prepared by simply placing an electron taken from the highest occupied molecular orbital (HOMO) into the lowest unoccupied molecular orbital (LUMO). , Thus, in spite of many previous efforts, a comprehensive description of the electronic structure and photodegradation pathways of S 8 rings, in particular with respect to the formation of triplet states, remains elusive. Here, to better characterize the nature of the excited electronic states and the possible ring-to-chain relaxation pathways upon photoexcitation, we combine time-dependent (TD)-DFT and highly correlated wave function STEOM-CCSD calculations to evaluate the ground-state and excited-state electronic and geometric structures of the S 8 molecular materials.…”

mentioning

confidence: 99%

Ring-to-Chain Structural Relaxation of Elemental Sulfur upon Photoexcitation

Cho

Pratik

Pyun

et al. 2022

ACS Materials Lett.

View full text Add to dashboard Cite

The emergence of high sulfur content polymeric materials and their applications in a number of important areas call for a comprehensive understanding of the chemical and physical properties of elemental sulfur. In spite of many earlier efforts, a thorough description of the electronic structure and photorelaxation pathways of the S8 ring, the thermodynamically stable structure of elemental sulfur, remains largely unexplored. It can be expected that the photoinduced homolytic processes of S8 and intermediates are analogous to those in the species observed via thermally induced processes. Here, we combine time-dependent density functional theory (TD-DFT) and highly correlated wave function STEOM-CCSD calculations to describe the photoinduced homolytic pathways in both singlet and triplet excited-state manifolds and explore the ring-to-chain relaxations. The results of our calculations indicate that, upon photoexcitation, the S8 ring undergoes a fast intersystem crossing (ISC) from the S1 state to the triplet manifold, with estimated ISC rates of over 1011 s–1 as a result of significant spin–orbit couplings. The TD-DFT geometry relaxations in the singlet and triplet excited states underline that, upon photoexcitation, an S–S bond within the S8 ring readily undergoes homolytic fragmentation, a feature that is thus also expected upon thermal excitation. Importantly, this represents the first theoretical demonstration that the molecular structure in the triplet state evolves from a ring configuration to an open chain configuration that carries a diradical character, which is consistent with the reported photoinduced polymerization processes in elemental sulfur.

show abstract

Structural studies on fluid sulfur at high temperatures and high pressures: II. Molecular structure obtained by ab initio molecular dynamics simulations

Cited by 5 publications

References 21 publications

Surface/Interface Structure and Chemistry of Lithium–Sulfur Batteries: From Density Functional Theory Calculations’ Perspective

Surface/Interface Structure and Chemistry of Lithium–Sulfur Batteries: From Density Functional Theory Calculations’ Perspective

Collective dynamics of liquid sulphur across the polymerisation transition temperature probed by inelastic x-ray scattering

Ring-to-Chain Structural Relaxation of Elemental Sulfur upon Photoexcitation

Contact Info

Product

Resources

About