Regarding expressions of the oscillatory patterns in the 2D spectra of a displaced oscillator model

There have been many efforts recently in analyzing the oscillation patterns in a two-dimensional electronic spectrum to characterize vibmnic couplings. A displaced oscillator model with a four-level vibmnic system (4LvS) is a commonly used model to approximate such phenomena. Although this model is related to an electronic two-level system coupled to a harmonic oscillator (2LScHO) model, there has not been a formal study to connect the two models. Here, we show explicitly that the former is a special case of the latter. We provide a detailed description of how the expressions for the 2D spectral peak amplitudes of the 4LvS model can be derived from the electronic 2LScHO model at T = 0 K. We also demonstrate that the two-dimensional Fourier maps of the 4LvS model are still good representatives of the more general electronic 2LScHO model at T not equal 0 K.

Automated summary

Efforts have been made to analyze oscillation patterns to characterize vibronic couplings in a two-dimensional electronic spectrum. A commonly used displaced oscillator model with a four-level vibronic system has been shown to be a special case of an electronic two-level system coupled to a harmonic oscillator model. The study provides a detailed description of how the two models are interconnected and showcases their applicability under different temperature conditions.