Day Paul N, Nguyen Kiet A, Pachter Ruth
Materials and Manufacturing Directorate, Air Force Research Laboratory, Wright Patterson Air Force Base, Ohio 45433, General Dynamics Information Technology, Inc., 5200 Springfield Street, Dayton, Ohio 45431, and UES, Inc., 4401 Dayton Xenia Road, Dayton, Ohio 45432.
J Chem Theory Comput. 2010 Sep 14;6(9):2809-21. doi: 10.1021/ct100139t. Epub 2010 Aug 9.
The one- (OPA) and two-photon (TPA) absorption spectra have been calculated for a gold dimer, for a monothiolated gold dimer anion, for a thiolated gold cluster Au25(SH)18, whose structure has been determined, and for a proposed cluster Au12(SR)9 using time-dependent density functional theory (TDDFT). Geometry optimization with different exchange-correlation (X-C) functionals yielded small differences which had significant consequences in the spectra calculations. The calculated excitation energies of Au25(SH)18(-1) are in excellent agreement with experiment when the local density approximation Xα-optimized geometry is used with the B3LYP X-C functional. The CAMB3LYP and mCAM functionals yielded OPA results in good agreement with experiment for the dimer systems and the larger clusters. The super-atom theory was useful in analyzing the electronic transitions in the larger clusters. TPA was dominated by resonance effects, and the calculated cross-sections displayed a strong X-C functional dependence.
利用含时密度泛函理论（TDDFT）计算了金二聚体、单硫醇化金二聚体阴离子、结构已确定的硫醇化金簇Au25(SH)18以及一种推测的簇Au12(SR)9的单光子（OPA）吸收光谱和双光子（TPA）吸收光谱。使用不同的交换关联（X-C）泛函进行几何优化产生了微小差异，这些差异在光谱计算中产生了重大影响。当使用局部密度近似Xα优化的几何结构与B3LYP X-C泛函时，计算得到的Au25(SH)18(-1)的激发能与实验结果非常吻合。对于二聚体系统和较大的簇，CAMB3LYP和mCAM泛函给出的OPA结果与实验结果吻合良好。超原子理论有助于分析较大簇中的电子跃迁。TPA主要受共振效应支配，计算得到的截面显示出对X-C泛函的强烈依赖性。
