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Theoretical Investigation of Relaxation Dynamics in Au38(SH)24 Thiolate-Protected Gold Nanoclusters
The Journal of Physical Chemistry C ( IF 3.3 ) Pub Date : 2018-07-05 , DOI: 10.1021/acs.jpcc.8b03595 Ravithree D. Senanayake 1 , Emilie B. Guidez 2 , Amanda J. Neukirch 3 , Oleg V. Prezhdo 4 , Christine M. Aikens 1
The Journal of Physical Chemistry C ( IF 3.3 ) Pub Date : 2018-07-05 , DOI: 10.1021/acs.jpcc.8b03595 Ravithree D. Senanayake 1 , Emilie B. Guidez 2 , Amanda J. Neukirch 3 , Oleg V. Prezhdo 4 , Christine M. Aikens 1
Affiliation
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A subtle change in the electronic structure of thiolate-protected noble metal nanoparticles can result in distinctive energy relaxation dynamics. Corresponding investigations on different sizes and structures of thiolate-protected gold nanoclusters reveal their physical and chemical properties for further development of catalytic applications. In this work, we performed nonradiative relaxation dynamics simulations of the Au38(SH)24 nanocluster to describe electron-vibrational energy exchange. The core and higher excited states involving semiring motifs lying in the energy range of 0.00–2.01 eV are investigated using time-dependent density functional theory (TDDFT). The surface hopping method with decoherence correction combined with real-time TDDFT is used to assess the quantum dynamics. The Au23 core relaxations are found to occur in the range of 2.0–8.2 ps. The higher excited states that consist of core–semiring mixed or semiring states give ultrafast decay time constants in the range of 0.6–4.9 ps. Our calculations predict that the slowest individual state decay of S11 or the slowest combined S11–S12, S1–S2–S6–S7 and S4–S5–S9–S10 decay involves intracore relaxations. The analysis of the phonon spectral densities and the ground state vibrational frequencies suggests that the low frequency (25 cm–1) coherent phonon emission reported experimentally could be the bending of the bi-icosahedral Au23 core or the “fan blade twisting” mode of two icosahedral units.
中文翻译：
Au 38（SH）24硫醇盐保护的金纳米团簇弛豫动力学的理论研究
硫醇盐保护的贵金属纳米粒子的电子结构的细微变化可导致独特的能量弛豫动力学。对硫醇盐保护的金纳米团簇的不同尺寸和结构的相应研究揭示了其物理和化学性质，可用于进一步发展催化应用。在这项工作中，我们对Au 38（SH）24进行了非辐射弛豫动力学模拟纳米簇来描述电子振动能量交换。使用依赖于时间的密度泛函理论（TDDFT）研究了涉及在0.00-2.01 eV能量范围内的半环图案的核心和更高的激发态。结合了去相干校正和实时TDDFT的表面跳变方法用于评估量子动力学。发现Au 23的核弛豫发生在2.0–8.2 ps的范围内。由磁芯-半混合或半环态组成的较高激发态可提供0.6-4.9 ps范围内的超快衰减时间常数。我们的计算预测，S 11的单个状态衰减最慢或S 11 –S 12，S 1 –S 2组合的最慢–S 6 –S 7和S 4 –S 5 –S 9 –S 10衰减涉及核内弛豫。对声子频谱密度和基态振动频率的分析表明，实验报道的低频（25 cm –1）相干声子发射可能是双二十面体Au 23芯的弯曲或“扇形扭曲”模式。两个二十面体单元。
更新日期：2018-07-08
中文翻译：
Au 38（SH）24硫醇盐保护的金纳米团簇弛豫动力学的理论研究
硫醇盐保护的贵金属纳米粒子的电子结构的细微变化可导致独特的能量弛豫动力学。对硫醇盐保护的金纳米团簇的不同尺寸和结构的相应研究揭示了其物理和化学性质，可用于进一步发展催化应用。在这项工作中，我们对Au 38（SH）24进行了非辐射弛豫动力学模拟纳米簇来描述电子振动能量交换。使用依赖于时间的密度泛函理论（TDDFT）研究了涉及在0.00-2.01 eV能量范围内的半环图案的核心和更高的激发态。结合了去相干校正和实时TDDFT的表面跳变方法用于评估量子动力学。发现Au 23的核弛豫发生在2.0–8.2 ps的范围内。由磁芯-半混合或半环态组成的较高激发态可提供0.6-4.9 ps范围内的超快衰减时间常数。我们的计算预测，S 11的单个状态衰减最慢或S 11 –S 12，S 1 –S 2组合的最慢–S 6 –S 7和S 4 –S 5 –S 9 –S 10衰减涉及核内弛豫。对声子频谱密度和基态振动频率的分析表明，实验报道的低频（25 cm –1）相干声子发射可能是双二十面体Au 23芯的弯曲或“扇形扭曲”模式。两个二十面体单元。
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