Lu Haoran, Fang Wei-Hai, Long Run
College of Chemistry, Key Laboratory of Theoretical & Computational Photochemistry of Ministry of Education, Beijing Normal University, Beijing 100875, People's Republic of China.
J Am Chem Soc. 2024 Jul 17;146(28):19547-19554. doi: 10.1021/jacs.4c06654. Epub 2024 Jul 8.
We simulated hot-electron relaxation in black phosphorus using the nonadiabatic molecular dynamics (NA-MD) approach with a non-Condon effect in momentum space beyond the harmonic approximation. By comparing simulations at the Γ point in a large supercell with those using a few -points in a smaller supercell─while maintaining the same number of electronic states within the same energy range, we demonstrate that both setups yield remarkably consistent energy relaxation times, regardless of the initial state energy. This consistency arises from the complementary effects of supercell size in real space and the number of -points in the reciprocal space. This finding confirms that simulations at a single -point in large size supercells are an effective approximation for NA-MD with a non-Condon effect. This approach offers significant advantages for complex photophysics, such as intervalley scattering and indirect bandgap charge recombination, and is particularly suitable for large systems without the need for a harmonic approximation.
我们使用非绝热分子动力学（NA-MD）方法，在超越简谐近似的动量空间中考虑非康登效应，模拟了黑磷中的热电子弛豫。通过比较大超胞中Γ点处的模拟与小超胞中少数点处的模拟（同时在相同能量范围内保持相同数量的电子态），我们证明，无论初始态能量如何，两种设置都能产生非常一致的能量弛豫时间。这种一致性源于实空间中超胞尺寸与倒易空间中k点数量的互补效应。这一发现证实，在大尺寸超胞中的单点模拟是具有非康登效应的NA-MD的一种有效近似。这种方法对于复杂的光物理过程，如能谷间散射和间接带隙电荷复合，具有显著优势，并且特别适用于无需简谐近似的大系统。
