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-dimethylformam ide (DMF). We have studied the concentration dependence of binary solu tions of FA and NMF using DMF, water, and acetonitrile as cosolvents. Our results show an underdamped librational motion with a period of ab out 100 cm-1 in both FA and NMF, which also occurs in the binary solut ions. The significance of these results for ultrafast chemical reactio ns in solution is discussed.