Vibrational spectrum of Li2B4O7 crystals

Vdovin, Alexander; Moiseenko, V. N.; Bürak, Ya. I.

doi:10.1134/1.1366750

Cited by 8 publications

(3 citation statements)

References 5 publications

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“…Mulliken charges obtained with 6-11G(Li), 6-21G*(B), 8-411G*(O) and 7-11G(2d)(Li), 6-21G(2d)(B), 8-411*(O) basis sets were 0.86 and 0.60 for LiBO 2 , giving a composition corresponding to x = 0.5. The effective charge in the Li 2 B 4 O 7 crystal calculation from longitudinal optical and transverse optical splitting in Raman spectroscopy was also reported as 0.8 . Although Li in the crystal system has a different coordination with O, these net charges are likely to be around 0.8–0.9.…”

Section: Resultsmentioning

confidence: 91%

First-Principles Molecular Dynamics Simulation and Conductivity Measurements of a Molten xLi₂O–(1 – x)B₂O₃ System

et al. 2013

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The electronic properties and atomic structure of a molten xLi2O-(1 - x)B2O3 system were investigated by measuring conductivity and using first-principles molecular dynamics (MD) simulations. The conductivities obtained were converted to a Li self-diffusion coefficient Dσ, using the Nernst-Einstein equation to assess charge transfer mechanisms. Dσ was compared with a Li self-diffusion coefficient, DNMR, which we measured in a previous study using high-temperature pulsed field gradient NMR. The DNMR/Dσ of xLi2O-(1 - x)B2O3 (0.2 ≤ x ≤ 0.5) at 1250 K ranged from 2.5 to 3.2, following the same trend as room temperature ionic liquids. First-principles MD simulations were performed using our own finite element density functional theory code, FEMTECK (finite element method-based total energy calculation) for molten xLi2O-(1 - x)B2O3 systems at 1250 K. We found that the O-B-O angle distribution functions were characterized by a peak at approximately 120°. Although the electron number from the electronic radial distribution function was arbitrary with regard to the cutoff distance, the net Li charge calculated from the integrated electron number surrounding Li was approximately 0.9 at 0.085 nm. The mean square displacement (MSD) of Li as a function of time was evaluated from the atomic configuration. Li self-diffusion coefficients calculated from the MSD were in better agreement with experimental results than they were using classical MD.

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Section: Resultsmentioning

confidence: 91%

First-Principles Molecular Dynamics Simulation and Conductivity Measurements of a Molten xLi₂O–(1 – x)B₂O₃ System

et al. 2013

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“…This behavior of the THz optical properties of the LB4 crystal may be associated with a complex phonon structure and its changes upon cooling [30][31][32]. For instance, the characteristic shape of the IR absorption spectrum in the region above 150 cm −1 shows a large number of absorption bands with a complex temperature behavior [30].…”

Section: Optical Properties In the Thz Rangementioning

confidence: 99%

Potential of Sub-THz-Wave Generation in Li2B4O7 Nonlinear Crystal at Room and Cryogenic Temperatures

et al. 2021

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Due to their high optical damage threshold, borate crystals can be used for the efficient nonlinear down-conversion of terawatt laser radiation into the terahertz (THz) frequency range of the electromagnetic spectrum. In this work, we carried out a thorough study of the terahertz optical properties of the lithium tetraborate crystal (Li2B4O7; LB4) at 295 and 77 K. Approximating the terahertz refractive index in the form of Sellmeier’s equations, we assessed the possibility of converting the radiation of widespread high-power laser sources with wavelengths of 1064 and 800 nm, as well as their second and third harmonics, into the THz range. It was found that four out of eight types of three-wave mixing processes are possible. The conditions for collinear phase matching were fulfilled only for the o − e → o type of interaction, while cooling the crystal to 77 K did not practically affect the phase-matching curves. However, a noticeable increase of birefringence in the THz range with cooling (from 0.12 to 0.16) led to an increase in the coherence length for o − o → e and e − e → e types of interaction, which are potentially attractive for the down-conversion of ultrashort laser pulses.

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“…В останні роки дослідженням коливальних спектрів Li2B4O7 присвячено цілий ряд робіт [13][14][15][16][17][18][19][20][21][22][23][24][25][26][27] Для наочності дані по ідентифікації коливальних мод склоподібного тетрабората літію наведено в таблиці.…”

Section: вступunclassified

КОМБІНАЦІЙНЕ РОЗСІЮВАННЯ СВІТЛА У СКЛОПОДІБНОМУ Li2B4O7

Puga¹,

Danyliuk²,

Rizak³

et al. 2019

J. of Chem. and Tech.

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Lithium tetraborate is a promising material to be used in the production of solid electrolytes and solid-state batteries. A powerful tool for investigating its structure in the B2O3-Li2O system is Raman spectroscopy. The Raman spectra were investigated using the XploRA PLUS (HORIBA Jobin Yvon) Raman spectrometer at the temperature of T = 300 K within the 70-2000 cm-1 range. The excitation wavelength was 785 nm, the spectral resolution was no worse than 1 cm-1. As a result of the study, we have determined the nature of vibrational modes. We detected a fine structure in the 70-400 cm-1 range, which we found to correspond to normal vibration of the lithium-oxygen structural complexes in the structure of [LiO6] frames, and also vibrations and librations of [LiO6] frame and the BO3 and BO4 groups in the structure of [B4O7] 2cluster as a whole. In the 400-800 cm-1 range the superposition of vibrations of [LiO4] clusters and [BO4] tetrahedrons takes place, whereas their normal vibrations are detected in the 800-1354 cm-1 range. In the 1300-2000 cm-1 range we observed the manifestation of two-phonon states, the normal vibrations of borate rings, and the symmetric stretching of the BO3 flat triangles, and detected two peaks that have not been observed previously. The obtained results show that the Raman spectra of glassy Li2B4O7 generally display a single-mode behavior and are caused by a combination of vibrations of different types which are interconnected via the frame structure of the glass consisting of complex boronoxygen and lithium-oxygen structural complexes.

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Vibrational spectrum of Li2B4O7 crystals

Cited by 8 publications

References 5 publications

First-Principles Molecular Dynamics Simulation and Conductivity Measurements of a Molten xLi₂O–(1 – x)B₂O₃ System

First-Principles Molecular Dynamics Simulation and Conductivity Measurements of a Molten xLi₂O–(1 – x)B₂O₃ System

Potential of Sub-THz-Wave Generation in Li2B4O7 Nonlinear Crystal at Room and Cryogenic Temperatures

КОМБІНАЦІЙНЕ РОЗСІЮВАННЯ СВІТЛА У СКЛОПОДІБНОМУ Li2B4O7

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Vibrational spectrum of Li2B4O7 crystals

Cited by 8 publications

References 5 publications

First-Principles Molecular Dynamics Simulation and Conductivity Measurements of a Molten xLi2O–(1 – x)B2O3 System

First-Principles Molecular Dynamics Simulation and Conductivity Measurements of a Molten xLi2O–(1 – x)B2O3 System

Potential of Sub-THz-Wave Generation in Li2B4O7 Nonlinear Crystal at Room and Cryogenic Temperatures

КОМБІНАЦІЙНЕ РОЗСІЮВАННЯ СВІТЛА У СКЛОПОДІБНОМУ Li2B4O7

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First-Principles Molecular Dynamics Simulation and Conductivity Measurements of a Molten xLi₂O–(1 – x)B₂O₃ System

First-Principles Molecular Dynamics Simulation and Conductivity Measurements of a Molten xLi₂O–(1 – x)B₂O₃ System