title: Ultrafast carbon-carbon single-bond rotational isomerization in room-temperature solution.
abstract: Generally, rotational isomerization about the carbon-carbon single bond in simple ethane derivatives in room-temperature solution under thermal equilibrium conditions has been too fast to measure. We achieved this goal using two-dimensional infrared vibrational echo spectroscopy to observe isomerization between the gauche and trans conformations of an ethane derivative, 1-fluoro-2-isocyanato-ethane (1), in a CCl4 solution at room temperature. The isomerization time constant is 43 picoseconds (ps, 10(-12) s). Based on this value and on density functional theory calculations of the barrier heights of 1, n-butane, and ethane, the time constants for n-butane and ethane internal rotation under the same conditions are approximately 40 and approximately 12 ps, respectively.
authors.affiliation: Department of Chemistry, Stanford University, Stanford, CA 94305, USA.
authors.forename: Junrong
authors.initials: J
authors.lastname: Zheng
authors.forename: Kyungwon
authors.initials: K
authors.lastname: Kwak
authors.forename: Jia
authors.initials: J
authors.lastname: Xie
authors.forename: M D
authors.initials: MD
authors.lastname: Fayer