Al 12 and the Al @ Al 12 clusters
Al 12 and the Al @ Al 12 clusters
复制标题
DOI：
10.1103/physreva.58.383
复制
发表时间：
1998-07
影响因子：
2.9
通讯作者：
J. Fowler;J. Ugalde
中科院分区：
文献类型：
--
作者：
J. Fowler;J. Ugalde
Ecker等人最近对${\ mathm {Al}}_{77}$簇的实验表征[Nature 387,379(1997)]详细描述了一个迷人的洋葱状结构，我们在这里报告其内核。对${\mathrm{Al}}_{12}$和${\mathrm{Al}\mathrm{@}\mathrm{Al}}_{12}$进行了详细的研究。使用密度泛函方法和具有有效核心势的基集对势能面进行了检查。用这种方法定位的稳定点，然后用三zeta加双极化尺寸的全电子基集进一步分析。在${\ maththrm {Al}}_{12}$表面上找到了两个平稳点，一个是${D}_{5d}$对称的交错极小点，另一个是${D}_{5h}$对称的重叠构象中的Hessian阶鞍点。研究了${\ matthrm {Al}\ matthrm {@}\ matthrm {Al}}_{12}$的阳离子、中性和阴离子表面。在阴离子${\mathrm{Al}\mathrm{@}\mathrm{Al}}_{12}^{\ensuremath{-}}$簇中发现了与${\mathrm{Al}}_{12} ^{\ mathrm{Al}}_{12}^{\ mathrm{Al}}_{12}^{\ensuremath{-}}$簇类似的结构，尽管在这种情况下交错最小值具有二十面体对称，重叠的驻点是一个真正的过渡态。对于阳离子${\ mathm {Al}}_{13}^{+}$簇，没有找到笼中原子\char21{}型结构，但对于中性簇发现了一个最小值。这个${C}_{1}$的最小值与Ecker的${\ mathm {Al}}_{77}$簇的核心惊人地一致，该簇的中心到表面的键长范围从2.635到2.850 \AA{}，平均长度为2.744 \AA{}。
The recent experimental characterization of the ${\mathrm{Al}}_{77}$ cluster by Ecker et al. [Nature 387, 379 (1997)] detailed a fascinating onionlike structure whose inner core we report on here. The clusters ${\mathrm{Al}}_{12}$ and ${\mathrm{Al}\mathrm{@}\mathrm{Al}}_{12}$ have been studied in detail. Potential-energy surfaces have been examined using density-functional methodology and basis sets with effective core potentials. The stationary points located with this methodology were then further analyzed using full-electron basis sets of triple-zeta plus double polarization size. Two stationary points have been located on the ${\mathrm{Al}}_{12}$ surface, a staggered minimum of ${D}_{5d}$ symmetry and a saddle point of Hessian order three in an eclipsed conformation with ${D}_{5h}$ symmetry. The cationic, neutral, and anionic surfaces of ${\mathrm{Al}\mathrm{@}\mathrm{Al}}_{12}$ were explored. Structures similar to the ${\mathrm{Al}}_{12}$ stationary points were found for the anionic ${\mathrm{Al}\mathrm{@}\mathrm{Al}}_{12}^{\ensuremath{-}}$ cluster though in this case the staggered minimum had icosahedral symmetry and the eclipsed stationary point was a true transition state. No atom-in-a-cage\char21{}type structure could be located for the cationic ${\mathrm{Al}}_{13}^{+}$ cluster, but one minimum was found for the neutral. That ${C}_{1}$ minimum is in astonishing agreement with the core of Ecker's ${\mathrm{Al}}_{77}$ cluster having center-to-surface bond lengths that range from 2.635 to 2.850 \AA{} and average 2.744 \AA{}.