We systematically investigate the structural, electronic and magneticproperties of Mn$_n$ clusters ($n =$ 2$-$20) within the {\it ab-initio}pseudopotential plane wave method using generalized gradient approximation forthe exchange-correlation energy. A new kind of icosahedral structural growthhas been predicted in the intermediate size range. Calculated magnetic momentsshow an excellent agreement with the Stern-Gerlach experiment. A transitionfrom ferromagnetic to ferrimagnetic Mn$-$Mn coupling takes place at $n=$ 5 andthe ferrimagnetic states continue to be the ground states for the entire sizerange. Possible presence of multiple isomers in the experimental beam has beenargued. No signature of non-metal to metal transition is observed in this sizerange and the coordination dependence of $d-$electron localization isdiscussed.
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机译：我们使用交换梯度相关能量的广义梯度近似方法，系统地研究了{\ it ab-initio}伪电位平面波方法中Mn $ _n $团簇（$ n = $ 2 $-$ 20）的结构，电子和磁性。在中等尺寸范围内，已经预测出一种新型的二十面体结构生长。计算出的磁矩与Stern-Gerlach实验显示出极好的一致性。在$ n = $ 5处发生从铁磁耦合到亚铁磁Mn $-$ Mn的耦合，并且在整个尺寸范围内，亚铁磁态仍然是基态。在实验束中可能存在多种异构体。在该尺寸范围内未观察到非金属到金属过渡的特征，并且讨论了$ d- $电子本地化的配位依赖性。
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