Nonlinear Vibronic and Electronic Spectroscopy of Molecules in the Condensed Phase

实验物理化学计划支持康奈尔大学的安德烈亚斯·阿尔布雷希特继续他的研究，即在使用纳秒脉冲的凝聚相光谱学中使用“噪声”光来实现飞秒尺度的时间分辨率。利用一种新的图解技术，将基于光的噪声计时正式地推广到非线性光谱中。重点研究了二阶和三阶非线性电极化率。噪声光干涉图的二维阵列检测将被纳入，以将数据采集缩短近两个数量级。这些新的光谱技术可能会导致更准确的振动频率测量，并揭示凝聚相中多原子分子的驰豫过程和相干转移。这种技术非常实用的优点是，纳秒时间域中的噪声光谱可以探测接近飞秒区域的动力学，而不需要(昂贵的)相干飞秒脉冲。

The Experimental Physical Chemistry Program supports Andreas Albrecht of Cornell University in his continuing studies on the use of `noisy` light to achieve femtosecond scale time resolution in condensed phase spectroscopy using nanosecond pulses. The noisy light-based timing is formally generalized to nonlinear spectroscopies using a new diagrammatic technique. Focus is on second and third order nonlinear electrical susceptibilities. Two-dimensional array detection of the noisy light interferograms will be incorporated to shorten data acquisition by nearly two orders of magnitude. These new spectroscopic techniques will potentially lead to more accurate measurements of vibrational frequencies and shed light on relaxation processes and coherence transfer in polyatomic molecules in condensed phases. The very practical advantage of this technique is that noisy light spectra in the nanosecond time domain can probe dynamics approaching the femtosecond regime, without the need for (expensive) coherent femtosecond pulses.