Department of Chemistry, University of Nevada Las Vegas, 4505 Maryland Parkway, Las Vegas, NV 89154, USA.
Phys Chem Chem Phys. 2009 Nov 21;11(43):10003-8. doi: 10.1039/b914610e. Epub 2009 Sep 21.
All-electron scalar relativistic calculations of the geometric and electronic structures of neutral subnanometer Tc(n) (n = 2-15) clusters have been performed using spin-polarized density functional theory. It is shown that the structural evolution of Tc(n) clusters from n = 3 to n = 8 is similar to Mn clusters, which also belong to the group of VIIB transition metals. The calculated binding energy per atom varies gradually from 0.65 eV for Tc(2) to 2.35 eV for Tc(15). The computed electron affinity and ionization potential follow the classical electrostatic metallic droplet model for clusters larger than Tc(6) and converge asymptotically to the experimental value of the bulk Tc work function. A study of the kinetic stability of Tc clusters in terms of the second difference of binding energies and the energy gap between the frontier orbital states predicts Tc(3)(D(3h)), Tc(4)(T(d)), Tc(6)(O(h)), Tc(12)(I(h)), and Tc(13)(I(h)) to be the most stable clusters. Vibrational spectra of Tc clusters are also provided for further experimental identification.
采用自旋极化密度泛函理论对中性亚纳米 Tc(n)（n = 2-15）团簇的几何和电子结构进行了全电子标量相对论计算。结果表明，Tc(n)团簇从 n = 3 到 n = 8 的结构演化与 Mn 团簇相似，Mn 团簇也属于 VIIB 过渡金属组。计算得到的每个原子的结合能从 Tc(2)的 0.65 eV 逐渐增加到 Tc(15)的 2.35 eV。对于大于 Tc(6)的团簇，计算得到的电子亲和能和电离势符合经典静电金属液滴模型，并渐近收敛到体 Tc 功函数的实验值。根据结合能的二阶差分和前沿轨道态之间的能隙，研究了 Tc 团簇的动力学稳定性，预测 Tc(3)(D(3h))、Tc(4)(T(d))、Tc(6)(O(h))、Tc(12)(I(h))和 Tc(13)(I(h))是最稳定的团簇。还提供了 Tc 团簇的振动光谱，以进行进一步的实验鉴定。
