Carbon Tunneling from a Single Quantum State
Peter S. Zuev,1
Robert S. Sheridan,1*
Titus V. Albu,2
Donald G. Truhlar,2*
David A. Hrovat,3
Weston Thatcher Borden3*
We observed ring expansion of 1-methylcyclobutylfluorocarbene at 8 kelvin, a reaction that involves carbon tunneling. The measured rate
constants were 4.0 × 10
6 per second in nitrogen and
4 × 105 per second in argon. Calculations indicated
that at this temperature the reaction proceeds from a single quantum
state of the reactant so that the computed rate constant has achieved a
temperature-independent limit. According to calculations, the tunneling
contribution to the rate is 152 orders of magnitude greater than the
contribution from passage over the barrier. We discuss environmental
effects of the solid-state inert-gas matrix on the reaction rate.
1 Department of Chemistry 216, University of
Nevada, Reno, NV 89557, USA.
2 Department of
Chemistry and Supercomputer Institute, University of Minnesota,
Minneapolis, MN 55455-0431, USA.
3 Department of
Chemistry, Box 351700, University of Washington, Seattle, WA
98195-1700, USA.
*
To whom correspondence should be addressed. E-mail: rss{at}unr.edu
(R.S.S.); truhlar{at}umn.edu (D.G.T); borden{at}chem.washington.edu (W.T.B.)
