提出一种改进的ZORA(Zeroth-Order Regular Approximation to the Dirac Equation)方法,其单电子方程为:[σ·p(c^2/(2c^2-V_0))σ·p+V(r)]Ψ=εΨ式中VO为空间限域的势能函数:V_0(r=sum from A to(V_0~A(r_A)),r_A=|r-R_A|,V_...
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提出一种改进的ZORA(Zeroth-Order Regular Approximation to the Dirac Equation)方法,其单电子方程为:[σ·p(c^2/(2c^2-V_0))σ·p+V(r)]Ψ=εΨ式中VO为空间限域的势能函数:V_0(r=sum from A to(V_0~A(r_A)),r_A=|r-R_A|,V_0~A(r_A)=V^A(r_A{1+exp[α(r_A-r_0~A)]}^(-1)其中A表示分子的某个组成原子,R_A为A原子的位置矢量,V^A(r_A)为自由A原子的势函数,α和r_0~A为参数.改进的ZORA方法具有原来方法的所有优点,避免了原有ZORA方法因不满足标度变换不变性带来的缺陷,而且计算过程简单.具体计算表明,通过适当选择参数α和r_0~A,用本研究提出来的方法,在计算分子几何结构和键合能时,基本上消除了ZORA方法由于标度变换依赖性产生的误差.
Sb substituted Sm 2Fe 17-x Sb x materials have been synthesized by using modified reduction diffusion process with superfine Fe metal powder as a starting material. This synthetic route is unique and particularly usef...
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Sb substituted Sm 2Fe 17-x Sb x materials have been synthesized by using modified reduction diffusion process with superfine Fe metal powder as a starting material. This synthetic route is unique and particularly useful for the intermetallic compounds containing high volatile component. The substitution of Sb to the Sm 2Fe 17 significantly enhances the magnetic interaction between Fe atoms, which in turn, increases the Curie temperature of the materials. In addition, the chemical stability of Sm 2Fe 17 can also be improved by Sb substitution.
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