The Adiabatic Ionization Energy of the Vinoxy Radical
Megan R. Bentley1 , James H. Thorpe1 , Branko Ruscic2 and John F. Stanton1
1 University of Florida, Quantum Theory Project, Gainesville, FL 32611
2 Chemical Science and Engineering Division, Argonne National Laboratory, Argonne, IL 60439
Vinoxy (C2H3O) is a well-known, resonance-stabilized alkenyl radical prototype. There is a wealth of literature investigating the spectroscopy, dynamics and bonding in this radical, as it is a vital player in processes ranging from high-temperature combustion to atmospheric chemistry. Much less is known about its adiabatic ionization energy due to the substantial geometry change the radical undergoes upon ionization. In its ground state, vinoxy is planar and acyclic, but cyclizes to an oxirane as the methylene group in the cation twists through 90 degrees to form what is called the oxiranyllium cation. This geometry change results in poor Franck-Condon overlap in the origin region, complicating experimental determinations of this quantity. Using the High-Accuracy Extrapolated Thermochemistry (HEAT) approach, the adiabatic ionization energy connecting the ground state of vinoxy with that of the oxiranyllium cation is determined. The AIE is also calculated between vinoxy and the triplet state of the cation, in which the geometry change is less pronounced.