Solid Tritium Breeder Materials-Li₂O and LiAlO₂: A Data Base Review

Validation of potential models for Li2O in classical molecular dynamics simulation

“…The superionic critical temperatures were overestimated in FIT-HF and FIT-LDA, as the same with the melting point. In contrast, FIT-GGA and FIT-EMP provided melting points and superionic critical temperatures comparable to the experimental results [6][7][8]. These results can be associated with the energy variations induced by the distortions, to which FIT-HF and FIT-LDA possess higher resistance than FIT-GGA and FIT-EMP, as shown in Fig.…”

“…The FIT-HF, FIT-LDA and FIT-GGA models were fitted to the ab initio calculation results by means of the Hartree-Fock (HF) calculation [3], DFT calculation with local density approximation (LDA) [4], and DFT calculation with generalized gradient approximation (GGA), respectively. On the other hand, FIT-EMP was constructed by empirical fitting to the experimental crystalline properties [5][6][7][8][9][10][11].…”

“…In the fitting of the FIT-EMP model, the lattice constant, the elastic constants, the bulk modulus, the Young's modulus, the Poisson's ratio and the dielectric constants were calculated under static conditions using the GULP code. Those simulated values were then assessed according to their consistency with experimental values [5][6][7][8][9][10][11]. Several sets of parameters that had agreed well with the experimental values were subsequently re-screened according to the melting point and the thermal expansion behavior estimated in the MD calculation using the DL-POLY code.…”

“…As reference data, the experimental values [5][6][7][8][9][10][11] and the DFT calculation results in Table 1 Summary of the crystalline properties simulated in the four potential models Ref. [12] and the present study are listed, together with the reported results given by the AIM model [13].…”

Pressure-induced antifluorite-to-anticotunnite phase transition in lithium oxide

“…Recent studies argue that a new phase is either hexagonal or orthorhombic [6], but the existence and nature of this phase and the pressure at which it is reached are still uncertain [7,8]. In further similarity to ice, for which a high-pressure, high-temperature superionic phase has been predicted [9], ambient pressure Li 2 O becomes superionic at temperatures above 1350 K [10], prior to melting at 1705 K [11]. In the superionic phase, oxygen ions constitute a rigid framework while lithium ions move from one tetrahedral site to another via octahedral interstitial sites.…”