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为了用一个无参数模式获得镁橄榄石所有晶核的电场梯度,提出了一个以密度函数为基础的能带结构重新计算方法。用广义梯度近似值法得到的~(25)Mg 的 V_(zz)与由实验值获得的 V_(zz)相差最大为1%,~(17)O 为2%。如果在换算中使用核四极矩动量值,则绝对值相差约为5%,不对称参数与实验值也相当一致。用一个校正梯度相关互换位势取得的不对称参数值,比用标准局部密度近似值法获得的值要好。四极矩耦合张量的主轴与结晶轴之间的夹角也与实验值相吻合。M1位最大的偏差为1.8°,M2位为0.6°。该计算可以用于评价~(17)O 电场梯度的3组实验数据。所有计算同时也明确提出了一种测定特定 O 原子电场梯度的方法。
In order to obtain the electric field gradient of all the nuclei of forsterite in a parameterless mode, a method of recalculating the energy band structure based on the density function was proposed. The V zz of ~ (25) Mg obtained by the generalized gradient approximation and the V zz obtained from the experimental values differ by a maximum of 1% and ~ (17) O by 2%. If the translation of the nuclear quadrupole moment momentum, the absolute difference of about 5%, the asymmetry parameters and experimental values are quite consistent. Asymmetric parameter values obtained with one correction gradient-dependent exchange potential are better than those obtained with the standard local density approximation. The angle between the principal axis and the crystal axis of the quadrupole moment coupling tensor also coincides with the experimental value. The maximum deviation of M1 is 1.8 ° and M2 is 0.6 °. This calculation can be used to evaluate three sets of experimental data of ~ (17) O field gradient. All calculations also explicitly proposed a method for determining the gradient of a particular O-atom electric field.