화학공학소재연구정보센터
Journal of Physical Chemistry B, Vol.112, No.42, 13167-13171, 2008
Ultrafast N-H Vibrational Dynamics of Cyclic Doubly Hydrogen-Bonded Homo- and Heterodimers
Hydrogen-bonded interfaces are essential structural elements in biology. Furthermore. they can mediate electron transport by coupling the electron to proton transfer within the interface. The specific hydrogen-bonding configuration and strength have a large impact on the proton transfer, which exchanges the hydrogen-bonded donor and acceptor species (i.e., NH center dot center dot center dot H -> N center dot center dot center dot HO). Modulations of the hydrogen-bonding environment, such as the hydrogen-bond stretch and twist modes, affect the proton-transfer dynamics. Here, we present transient grating and echo peak shift measurements of the NH stretch vibrations of four doubly hydrogen-bonded cyclic dimers in their electronic ground state. The equilibrium vibrational dynamics exhibit strong coherent modulations that we attribute to coupling of the high-frequency NH vibration to the low-frequency interdimer stretch and twist modes and not to interference between multiple Fermi resonances that dominate the substructure of the linear spectra.