Rapid Access to Ground- and Excited-State Properties of Gold Nanoclusters Coated with Organic Ligands: Evaluation of the DFTB Method Performance

Gold nanoclusters stand as promising building blocks
for solar
energy harvesting applications, luminescent materials, and catalytic
devices. At the frontier between molecular and metallic structures,
their large number of electrons prevent the use of the ab initio quantum
mechanics method to rationalize and predict their structure–property
relationships, especially when fully coated with organic ligands.
Using an approximate DFT-based scheme, namely, the density functional
tight-binding (DFTB), we demonstrate that it is possible to rapidly
access the ground- (geometry and electronic structure) and excited-state
(UV–visible absorption) properties of these nano-objects without
sacrificing the qualitative accuracy of its parent DFT, paving the
way toward a quantum material design of gold-organic nanodevices.

金纳米团簇（Gold nanoclusters）是一类极具应用前景的构筑基元，可用于太阳能收集、发光材料及催化器件领域。作为介于分子与金属结构之间的前沿体系，其所含大量电子使得从头算量子力学方法（ab initio quantum mechanics method）难以用于阐释并预测其构效关系，尤其是当其被有机配体完全包覆时。本研究采用基于密度泛函理论（DFT）的近似计算方案，即密度泛函紧束缚（DFTB）方法，证明可快速获取这类纳米结构的基态（几何结构与电子结构）与激发态（紫外-可见吸收）特性，且不会损失其母密度泛函理论的定性精度，为金基有机纳米器件的量子材料设计铺平了道路。