Multidimensional optical spectra are measured from the response of a material system to a sequence of laser pulses and have the capacity to elucidate specific molecular interactions and dynamics whose influences are absent or obscured in a conventional linear absorption spectrum. Interpretation of complex spectra is supported by theoretical modeling of the spectroscopic observable, requiring implementation of quantum dynamics for coupled electrons and nuclei. Performing numerically correct quantum dynamics in this context may pose computational challenges, particularly in the condensed phase. Semiclassical methods based on calculating classical trajectories offer a practical alternative. Here I review the recent application of some semiclassical, trajectory-based methods to nonlinear molecular vibrational and electronic spectra.

中文翻译：

---

从经典轨迹计算多维光谱

多维光谱是通过材料系统对一系列激光脉冲的响应来测量的，并且能够阐明特定的分子相互作用和动力学，其影响在传统的线性吸收光谱中不存在或模糊。对复杂光谱的解释由光谱可观测的理论模型支持，需要对耦合电子和原子核实施量子动力学。在这种情况下执行数值正确的量子动力学可能会带来计算挑战，特别是在凝聚相中。基于计算经典轨迹的半经典方法提供了一种实用的替代方案。在这里，我回顾了一些半经典的、基于轨迹的方法最近在非线性分子振动和电子光谱中的应用。