Department of Physics, Isfahan University of Technology, 84156-83111 Isfahan, Iran.
J Chem Phys. 2014 Feb 28;140(8):084314. doi: 10.1063/1.4865947.
We use static as well as time-dependent first-principles computations to study interaction of the CO, NO, and HCN molecules with the Ag8 nanocluster. The many-body based GW correction is applied for accurate description of the highest occupied (HOMO) and the lowest unoccupied (LUMO) molecular orbital levels. It is argued that the adsorption of these molecules changes the stable structure of Ag8 from Td to the more chemically active D(2d) symmetry. We discuss that the CO, NO, and HCN molecules prefer to adsorb on the atom of the cluster with significant contribution to both HOMO and LUMO, for the accomplishment of the required charge transfers in the systems. The charge back donation is found to leave an excess energy of about 110 meV on the NO molecular bond, evidencing potential application of silver clusters for NO reduction. It is argued that CO and specially NO exhibit strong physical interaction with the silver cluster and hence significantly modify the electronic and optical properties of the system, while HCN makes very week physical bonds with the cluster. The optical absorption spectra of the Ag8 cluster before and after molecule adsorption are computed and a nontrivial red shift is observed in the NO and HCN adsorbed clusters.
我们使用静态和时变第一性原理计算来研究 CO、NO 和 HCN 分子与 Ag8 纳米团簇的相互作用。应用基于多体的 GW 校正来准确描述最高占据（HOMO）和最低未占据（LUMO）分子轨道能级。有人认为，这些分子的吸附会改变 Ag8 的稳定结构，使其从 Td 对称性转变为更具化学活性的 D(2d)对称性。我们讨论了 CO、NO 和 HCN 分子更喜欢吸附在对 HOMO 和 LUMO 都有重要贡献的团簇原子上，以完成系统中所需的电荷转移。发现电荷反向捐赠会在 NO 分子键上留下约 110meV 的过剩能量，这表明银团簇在 NO 还原方面有潜在的应用。有人认为，CO 特别是 NO 与银团簇有很强的物理相互作用，因此会显著改变系统的电子和光学性质，而 HCN 与团簇形成非常弱的物理键。计算了分子吸附前后 Ag8 团簇的光学吸收光谱，观察到在吸附了 NO 和 HCN 的团簇中出现了非平凡的红移。
