Ultrafast vibrational spectroscopy in condensed phases

A variety of ultrafast vibrational excitation and probing methods are first discussed and it is shown that various vibrational spectroscopies can be devised by combining multiple excitation and probing methods. A few ultrafast vibrational spectroscopic methods in condensed phases, which have already been demonstrated and used to study vibrational relaxation phenomena and structural analysis of small polypeptides, are briefly summarized. Then, a number of novel ultrafast vibrational spectroscopies that have been theoretically investigated are discussed by emphasizing their differences from other existing methods. Perspectives on how these ultrafast vibrational spectroscopies in centrosymmetric and non-centrosymmetric condensed phases can be applied to the investigations of chemical reaction dynamics, solvation dynamics, time-dependent structural evolutions of polyatomic molecules such as proteins will be mentioned.