FEMTOSECOND DYNAMICS OF HYDROGEN-BONDING SOLVENTS - FORMAMIDE AND N-METHYLFORMAMIDE IN ACETONITRILE, DMF, AND WATER

We have used optical-heterodyne-detected optical Kerr effect (OHD-OKE) spectroscopy to measure the ultrafast dynamical profile of the amide series formamide (FA), N-methylformamide (NMF), and N,N-dimethylformamide (DMF). We have studied the concentration dependence of binary solutions of FA and NMF using DMF, water, and acetonitrile as cosolvents. Our results show an underdamped librational motion with a period of about 100 cm-1 in both FA and NMF, which also occurs in the binary solutions. The significance of these results for ultrafast chemical reactions in solution is discussed.