A first-principles study on the quantum tunneling of methylhydroxycarbene isomerization in various solvents

Abstract Quantum tunneling phenomenon allows a high-barrier reaction to occur even though thermal energy is not sufficient to surmount the barrier. The phenomenon has been suggested to exist in the isomerization of methylhydroxycarbene which occured at 11 K. Here we study the quantum tunneling that occured in the isomerization of methylhydroxycarbene to acetaldehyde and to vinyl alcohol based on density functional calculations. The isomerization pathways are determined under the effect of various solvents which are modeled by polarizable continuum model (PCM). We use Wentzel-Kramers-Brillouin (WKB) approximation to calculate the tunneling probability (T) and extend the usefulness of T into isomerization rate. The results show that the solvents give a significant effect on the isomerization rate of methylhydroxycarbene to acetaldehyde but an insignificant one on the isomerization rate to vinyl alcohol.