Interionic interactions in transition metals
Interionic interactions in transition metals
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DOI：
10.1103/physrevb.28.4363
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发表时间：
1983-10
影响因子：
3.7
通讯作者：
J. Wills;W. Harrison
中科院分区：
文献类型：
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作者：
J. Wills;W. Harrison
通过扩展简单金属的近自由电子理论，包括过渡金属d带的影响，在恒定体积下得到的作为体积和离子构型的函数的过渡金属的总能量的近似计算提供了过渡金属的弹性和键合性质的定性的第一原理预测。如果允许对两个参数进行调整，那么这种描述就是定量的。s电子，处理与空芯赝势和费米理论，贡献的体积相关的条款和有效的两体之间的排斥力在恒定的总体积的离子。d− d矩阵元素的Harrison-Froyen公式与不同离子上d态之间重叠的类似处理和d态密度的Friedel模型相结合，以包括d带在总能量中的影响，导致与带宽成比例的键合项，随d− 5变化，以及d带重心的移动，随d− 8变化，这两者都可以表示为离子之间的有效两体相互作用，其与来自S电子的排斥结合，以描述恒定总体积下的性质。s-d杂交的效果被证明是大约占相对频带职业的转变。的体积依赖性进行测试，通过预测的平衡体积，体积模量，和Grüneisen常数为所有的过渡金属，和有效的声子势被用来预测的立方金属的弹性常数。所有的性质都可以手工计算，预测值和观测值之间的一致性与简单金属中相应理论的一致性一样好。
An approximate calculation of the total energy of a transition metal as a function of volume and ionic configuration at constant volume obtained by extending the nearly-free-electron theory of the simple metals to include the effects of transition-metal d bands provides a qualitative first-principles prediction of the elastic and bonding properties of the transition metals. The description becomes quantitative if one allows the adjustment of two parameters. The s electrons, treated with an empty-core pseudopotential and Thomas-Fermi theory, contribute volume-dependent terms and an effective two-body repulsive potential between ions at constant total volume. The Harrison-Froyen formulation of the d− d matrix elements is combined with a similar treatment of the overlap between d states on different ions and the Friedel model of the density of d states to include the effects of the d bands in the total energy, resulting in a bonding term proportional to the bandwidth, varying as d− 5, and a shift in the center of gravity of the d band, varying as d− 8, both of which can be expressed as effective two-body interactions between ions to be combined with the repulsion from the s electrons in describing properties at constant total volume. The effect of s− d hybridization is shown to be approximately accounted for by a shift in relative band occupations. The volume dependence is tested by prediction of the equilibrium volume, the bulk modulus, and a Grüneisen constant for all the transition metals, and the effective interionic potential is used to predict the elastic constants of the cubic metals. All properties can be calculated by hand; the agreement between predicted and observed values is as good as that obtained with the corresponding theory in the simple metals.