Several methods have been proposed to obtain the frequency fluctuation correlation function (FFCF) of a transition from the 2DES spectra without complicated fitting procedures. Although all were shown to give correct values in idealized conditions, this might not be applicable in real experimental circumstances. Here, we observe the effects of using different bandwidth excitation pulses in three commonly used methods: ellipticity, center line slope of slices along excitation (CLSω₁) and detection (CLSω₃) frequencies. The studies were performed on the Q_y transition of chlorophyll a. We show that the CLSω₃ method gives consistent results for all bandwidths used. For the other two methods, the recovered FFCF values decrease in magnitude with decreasing excitation pulse bandwidths. We also show that by applying the simplified expressions derived by Do et al., incorporating finite pulses in 2DES spectra simulation, we can recover accurate FFCFs using any of these methods.

已经提出了几种方法来从2DES频谱获得跃迁的频率波动相关函数（FFCF），而无需复杂的拟合过程。尽管所有数据都显示出在理想条件下的正确值，但这可能不适用于实际的实验环境。在这里，我们观察使用三种常用方法的不同带宽激励脉冲的影响：椭圆率，沿激励切片的中心线斜率（CLSω ₁）和检测（CLSω ₃）的频率。对叶绿素a的Q _y跃迁进行了研究。我们表明，CLSω ₃对于使用的所有带宽，该方法都能提供一致的结果。对于其他两种方法，恢复的FFCF值的大小随激励脉冲带宽的减小而减小。我们还表明，通过应用Do等人推导的简化表达式，在2DES频谱模拟中结合有限脉冲，我们可以使用这些方法中的任何一种来恢复精确的FFCF。