【摘要】 以密度泛函理论为基础,利用简化的胶体模型,在局域密度近似下研究金属中的空位型缺陷的电子结构和以正电子寿命为表征的缺陷谱.结果表明,随着空位尺度的增加,正电子寿命亦增加并直到饱和值.更多还原

【Abstract】 The electronic structure and positron annihilation lifetime for vacancy-like defects in metals are studied using a simplified colloid model and local density approximation based on the density functional theory. The programs for evaluating electron wave functions and positron annihilation lifetime for these defects have been developed and the electronic structure and positron annihilation lifetime for vacancy-like defects of various sizes in aluminum have been calculated. The results obtained are compared with experimental ones. The colloid model has been compared with Puska’s noninteracting atom model, and the scope for which the colloid model is valid has been investigated. It is shown that the colloid model is a useful tool for the calculation of electronic structure with small voids of a mean radius less than 4nm.更多还原