论文标题
内部转换率来自扩展的融化高斯近似：理论和验证
Internal Conversion Rates from the Extended Thawed Gaussian Approximation: Theory and Validation
论文作者
论文摘要
分子中非放射过程速率的理论预测是评估其发射特性的基础。在这种情况下，全局谐波模型已被广泛用于模拟振动光谱以及内部转换率，并预测光致发光量子产率。但是，这些简化的模型遭受了谐波近似固有的局限性，并且可能对计算的内部转换率产生严重影响。因此，更准确的半经典方法的发展是非常需要的。在这里，我们介绍了一种在时间依赖性半古典延长解冻高斯近似（ETGA）框架内计算非辐射率的程序。我们通过将ETGA方法与属于广泛使用的全局谐波模型类别的绝热和垂直谐波方法进行比较，系统地研究了ETGA方法的性能。它的性能在无法通过全球谐波模型进行充分处理的潜力中进行了测试，从摩尔斯的潜在的摩尔斯式潜力开始，然后具有双重井潜力。将计算出的辐射和非辐射性内部转换率与基于精确量子动力学的参考值进行了比较。我们发现，ETGA具有预测具有明显能量差距的Anharmonic系统中的内部转换率，而全球谐波模型被证明是不够的。
The theoretical prediction of the rates of nonradiative processes in molecules is fundamental to assess their emissive properties. In this context, global harmonic models have been widely used to simulate vibronic spectra as well as internal conversion rates and to predict photoluminescence quantum yields. However, these simplified models suffer from the limitations that are inherent to the harmonic approximation and can have a severe effect on the calculated internal conversion rates. Therefore, the development of more accurate semiclassical methods is highly desirable. Here, we introduce a procedure for the calculation of nonradiative rates in the framework of the time-dependent semi-classical Extended Thawed Gaussian Approximation (ETGA). We systematically investigate the performance of the ETGA method by comparing it to the the adiabatic and vertical harmonic method, which belong to the class of widely used global harmonic models. Its performance is tested in potentials that cannot be treated adequately by global harmonic models, beginning with Morse potentials of varying anharmonicity followed by a double well potential. The calculated radiative and nonradiative internal conversion rates are compared to reference values based on exact quantum dynamics. We find that the ETGA has the capability to predict internal conversion rates in anharmonic systems with an appreciable energy gap, whereas the global harmonic models prove to be insufficient.
