Abteilung für Physikalische Chemie mikroskopischer Systeme, Karlsruher Institut für Technologie, Kaiserstr. 12, 76128 Karlsruhe, Germany.
J Chem Phys. 2011 Jan 14;134(2):024311. doi: 10.1063/1.3518040.
By a combination of gas phase ion mobility measurements and relativistic density functional theory calculations with inclusion of spin-orbit coupling, we assign structures of lead cluster cations and anions in the range between 4 and 15 atoms. We find a planar rhombus for the tetramer, a trigonal bipyramid for the pentamer, and a pentagonal bipyramid for the heptamer, independent of charge state. For the hexamer, the cation and anion structures differ: we find an octahedron for the anion while the cation consists of fused tetrahedra. For the octamer, we find in both cases structures based on the pentagonal bipyramid motif plus adatom. For the larger clusters investigated we always find different structures for cations and anions. For example, Pb(12)(-) is confirmed to be a hollow icosahedron while Pb(12)(+) is a truncated filled icosahedron. Pb(13)(+) is a filled icosahedron but Pb(13)(-) is a hollow icosahedron with the additional atom capping a face. In order to get experimental information on the relative stabilities, we investigated the collision induced dissociation mass spectra for the different cluster sizes and charge states, and observe a strong correlation with the calculated fragmentation energies. Up to n = 13 the main fragmentation channel is atom loss; for the larger cluster sizes we observe fission into two large fragments. This channel is dominant for larger anions, less pronounced but clearly present for the cations.
通过气相离子迁移率测量和包含自旋轨道耦合的相对论密度泛函理论计算的结合，我们分配了 4 到 15 个原子范围内的铅团簇阳离子和阴离子的结构。我们发现四聚体为平面菱形，五聚体为三角双锥，七聚体为五边形双锥，与电荷状态无关。对于六聚体，阳离子和阴离子的结构不同：我们发现阴离子为八面体，而阳离子由融合的四面体组成。对于八聚体，我们在两种情况下都发现了基于五边形双锥基元和附加原子的结构。对于研究的较大簇，我们总是发现阳离子和阴离子的结构不同。例如，Pb(12)(-) 被确认为空心二十面体，而 Pb(12)(+) 是截顶填充二十面体。Pb(13)(+) 是填充的二十面体，但 Pb(13)(-) 是一个空心二十面体，额外的原子覆盖一个面。为了获得关于相对稳定性的实验信息，我们研究了不同簇大小和电荷状态的碰撞诱导解离质谱，观察到与计算的碎裂能之间存在很强的相关性。在 n = 13 之前，主要的碎裂通道是原子损失；对于较大的簇大小，我们观察到分裂成两个大碎片。这个通道对于较大的阴离子是主要的，对于阳离子则不那么明显，但明显存在。
