Numerical calculations of multiphoton molecular absorption
Numerical calculations of multiphoton molecular absorption
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DOI：
10.1103/physreva.106.013111
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发表时间：
2022-07
影响因子：
2.9
通讯作者：
B. Kaufman;P. Marquetand;T. Weinacht;T. Rozgonyi
中科院分区：
文献类型：
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作者：
B. Kaufman;P. Marquetand;T. Weinacht;T. Rozgonyi
受多光子驱动的泵浦-探测实验（如时间分辨光电子光谱学）的可能性的启发，我们通过求解强激光场中分子的含时薛定谔方程，进行了强场分子激发的本征态计算。通常这样的计算依赖于绝热消除，但在这里，我们直接使用大量的能量和电子结构计算获得的跃迁偶极矩。通过这种方式，我们捕获了一系列的多光子吸收阶数，从2到5，并自然地包括动态斯塔克位移。我们考虑了一系列的激光频率和强度来表征几个多光子共振和动态斯塔克位移。计算还包括对分子取向和几何形状的平均，但对冷冻核进行，这与非常短的激光脉冲（< 10 fs）的限制有关。在这里，我们专注于分子噻吩，然而，这些计算可以很容易地实现其他分子与适当的电子结构输入。
Motivated by the possibility of multiphoton-driven pump-probe experiments, such as time-resolved photoelec-tron spectroscopy, we carry out essential states’s calculations of strong-field molecular excitation by solving the time-dependent Schrödinger equation for a molecule in a high-intensity laser field. Usually such calculations rely on adiabatic elimination, but here we make direct use of a large number of energies and transition dipole moments obtained from electronic structure calculations. In this way, we capture a range of multiphoton absorption orders, from 2 to 5, and include dynamic Stark shifts naturally. We consider a range of laser frequencies and intensities to characterize several multiphoton resonances and dynamic Stark shifts. The calculations also include averaging over molecular orientation and geometry, but are carried out for frozen nuclei, which is relevant in the limit of very short laser pulses ( < 10 fs). Here we focus on the molecule thiophene; however, these calculations can easily be implemented for other molecules with appropriate electronic structure input.