Spectroscopic study of lithium oxide irradiated by fast neutrons

Masaki, Nobuo; Noda, K.; Watanabe, Hitoshi; Clemmer, R.G.; Hollenberg, G.W.

doi:10.1016/0022-3115(94)90967-9

Cited by 23 publications

(7 citation statements)

References 11 publications

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“…Diffusion and ionic conduction in Li 2 O are subjects of great interest due to the superionic behaviour of this material. Both theoretical and experimental investigations have been performed for Li 2 O on the energetic [21][22][23], electronic [23][24][25][26][27][28][29][30][31][32], and defect properties [29][30][31][32][33][34][35][36][37][38][39][40][41][42], and the ion conduction mechanism [1-3, 34, 35, 43-47].…”

Section: General Overviewmentioning

confidence: 99%

The ionic conductivity in lithium-boron oxide materials and its relation to structural, electronic and defect properties: insights from theory

Islam

Bredow

Heitjans

2012

J. Phys.: Condens. Matter

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We review recent theoretical studies on ion diffusion in (Li(2)O)(x)(B(2)O(3))(1-x) compounds and at the interfaces of Li(2)O :B(2)O(3) nanocomposite. The investigations were performed theoretically using DFT and HF/DFT hybrid methods with VASP and CRYSTAL codes. For the pure compound B(2)O(3), it was theoretically confirmed that the low-pressure phase B(2)O(3)-I has space group P3(1)21. For the first time, the structure, stability and electronic properties of various low-index surfaces of trigonal B(2)O(3)-I were investigated at the same theoretical level. The (101) surface is the most stable among the considered surfaces. Ionic conductivity was investigated systematically in Li(2)O, LiBO(2), and Li(2)B(4)O(7) solids and in Li(2)O:B(2)O(3) nanocomposites by calculating the activation energy (E(A)) for cation diffusion. The Li(+) ion migrates in an almost straight line in Li(2)O bulk whereas it moves in a zig-zag pathway along a direction parallel to the surface plane in Li(2)O surfaces. For LiBO(2), the migration along the c direction (E(A) = 0.55 eV) is slightly less preferable than that in the xy plane (E(A) = 0.43-0.54 eV). In Li(2)B(4)O(7), the Li(+) ion migrates through the large triangular faces of the two nearest oxygen five-vertex polyhedra facing each other where E(A) is in the range of 0.27-0.37 eV. A two-dimensional model system of the Li(2)O :B(2)O(3) interface region was created by the combination of supercells of the Li(2)O (111) surface and the B(2)O(3) (001) surface. It was found that the interface region of the Li(2)O:B(2)O(3) nanocomposite is more defective than Li(2)O bulk, which facilitates the conductivity in this region. In addition, the activation energy (E(A )) for local hopping processes is smaller in the Li(2)O :B(2)O(3) nanocomposite compared to the Li(2)O bulk. This confirms that the Li(2)O:B(2)O(3) nanocomposite shows enhanced conductivity along the phase boundary compared to that in the nanocrystalline Li(2)O.

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Section: General Overviewmentioning

confidence: 99%

The ionic conductivity in lithium-boron oxide materials and its relation to structural, electronic and defect properties: insights from theory

Islam

Bredow

Heitjans

2012

J. Phys.: Condens. Matter

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“…Diffusion and ionic conduction in Li 2 O are subjects of great interest due to the superionic behavior of this material. Both theoretical and experimental investigations have been performed for Li 2 O on the energetic − , electronic, − and defect properties, − and the ion conduction mechanism. ,,− …”

Section: Introductionmentioning

confidence: 99%

Theoretical Analysis of Structural, Energetic, Electronic, and Defect Properties of Li₂O

2006

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The structural, energetic, and electronic properties of stoichiometric and defective Li(2)O were studied theoretically. The reliability of the Perdew-Wang method in the framework of density functional theory (DFT), and of two DFT/Hartree-Fock hybrid methods (PW1PW and B3LYP), was examined by comparison of calculated and available experimental data. Atom-centered orbitals and plane waves were used as basis functions for the crystalline orbitals. For both cases, the basis set dependence of calculated properties was investigated. With most of the methods, good agreement with the experimental Li(2)O lattice parameter and cohesive energy was obtained. In accordance with experiment, the analysis of electronic properties shows that Li(2)O is a wide gap insulator. Among the considered methods, the hybrid methods PW1PW and B3LYP give the best agreement with experiment for the band gap. The formation of an isolated cation vacancy defect and an F center in Li(2)O were studied. The effect of local relaxation on the calculated defect formation energies and the defect-induced changes of electronic properties were investigated and compared to available experimental results. The migration of a Li(+) ion in Li(2)O bulk was investigated. The activation energy for the migration of a Li(+) ion from its regular tetrahedral site to an adjacent cation vacancy was calculated, including the effect of local relaxation. The calculated activation barriers, 0.27-0.33 eV, are in excellent agreement with experiment.

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“…It is known that, in an operating fusion reactor, the irradiation defects in the breeding materials will be generated by fast neutrons, energetic tritons (2.7 MeV) and helium ions (2.1 MeV) generated in 6 Li(n,a) 3 H reaction. It has been reported that such irradiation defects affect the tritium release and tritium inventory in the breeding materials [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15]. In the previous studies, the behavior of the irradiation defects in Li 2 O such as F þ centers and Li colloidal centers and the interaction between such defects and tritium generated with irradiation in Li 2 O have been studied with ESR, optical absorption, and other techniques.…”

Section: Introductionmentioning

confidence: 96%

Tritium release from neutron-irradiated Li2O sintered pellets: isothermal annealing of tritium traps

Tanifuji¹,

Yamaki²,

Jitsukawa³

2004

Journal of Nuclear Materials

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Spectroscopic study of lithium oxide irradiated by fast neutrons

Cited by 23 publications

References 11 publications

The ionic conductivity in lithium-boron oxide materials and its relation to structural, electronic and defect properties: insights from theory

The ionic conductivity in lithium-boron oxide materials and its relation to structural, electronic and defect properties: insights from theory

Theoretical Analysis of Structural, Energetic, Electronic, and Defect Properties of Li₂O

Tritium release from neutron-irradiated Li2O sintered pellets: isothermal annealing of tritium traps

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Spectroscopic study of lithium oxide irradiated by fast neutrons

Cited by 23 publications

References 11 publications

The ionic conductivity in lithium-boron oxide materials and its relation to structural, electronic and defect properties: insights from theory

The ionic conductivity in lithium-boron oxide materials and its relation to structural, electronic and defect properties: insights from theory

Theoretical Analysis of Structural, Energetic, Electronic, and Defect Properties of Li2O

Tritium release from neutron-irradiated Li2O sintered pellets: isothermal annealing of tritium traps

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Theoretical Analysis of Structural, Energetic, Electronic, and Defect Properties of Li₂O