论文标题
二维电子光谱的三阶响应函数的直接从头静止评估
On-the-fly ab initio semiclassical evaluation of third-order response functions for two-dimensional electronic spectroscopy
论文作者
论文摘要
二维电子光谱的从头算计算是一个不断扩展的场，其目标是在经常使用的简单，几维模型上改进来解释实验。在这里，我们基于单个标志性的半经典融化高斯近似，提出了一种准确且计算负担得起的方法，以评估二维电子光谱。重要的是，该方法对于具有模式位移，模式频率变化和模式耦合（Duschinsky效应）的任意谐波电位精确，但也可以部分解释涉及势能表面的非谐波性。我们测试了其在一组模型摩尔斯电位上的准确性，并使用它来研究对苯酚线性和二维电子光谱的非谐性和duschinsky的影响。我们发现，在该分子中，非谐度效应很弱，而Duschinsky旋转和模式频率的变化必须包括在精确的模拟中。相反，使用广泛的位移谐波振荡器模型仅捕获问题的基本物理，但无法再现正确的振动线形。
Ab initio computation of two-dimensional electronic spectra is an expanding field, whose goal is improving upon simple, few-dimensional models often employed to explain experiments. Here, we propose an accurate and computationally affordable approach, based on the single-trajectory semiclassical thawed Gaussian approximation, to evaluate two-dimensional electronic spectra. Importantly, the method is exact for arbitrary harmonic potentials with mode displacement, changes in the mode frequencies, and inter-mode coupling (Duschinsky effect), but can also account partially for the anharmonicity of the involved potential energy surfaces. We test its accuracy on a set of model Morse potentials and use it to study anharmonicity and Duschinsky effects on the linear and two-dimensional electronic spectra of phenol. We find that in this molecule, the anharmonicity effects are weak, whereas the Duschinsky rotation and the changes in the mode frequencies must be included in accurate simulations. In contrast, the widely used displaced harmonic oscillator model captures only the basic physics of the problem but fails to reproduce the correct vibronic lineshape.
