Broadband two dimensional infrared spectroscopy of cyclic amide 2-Pyrrolidinone
In the past one-and-a-half decade there has been a significant methodological and technological development of two dimensional infrared (2DIR) spectroscopy, which unfolds many underlying physical and chemical processes of complex molecules, especially for biological molecules. Due to the extreme technical difficulties and non-uniform performance of ultrafast laser, so far, the method has been mostly applied to a small spectral region. A rather simple experimental methodology is presented here which is able to cover a broad spectral range from 1500 cm−1 to 3500 cm−1 to explore the molecular structure of cyclic amide, 2-Pyrrolidinone, via the time-resolved coupling of CO, CH and NH stretch vibrations. The signature of the coherent as well as incoherent coupling has been found. The amide-I band is incoherently coupled to CH and NH stretch vibrations and acts as an acceptor mode for vibrational energy relaxation from CH and NH stretch vibrations.