The rate constant for the automerization of vinyl radical: A theoretical approach using the Complete Active Space Self Consistent Field method

Abstract

The Complete Active Space Self Consistent Field method (CASSCF) was utilized to investigate the rate constant for the automerization of vinyl radical. Using an enlarged active space including all valence electrons, thus producing a total number of 213,444 Configuration State Functions (CSFs) the rate constant for the automerization is of the order of 109 s−1 or 1010 s−1 in case of using the vibrational energy splitting tunneling method with the corresponding energy barrier height, involving the zero point vibrational energy corrections, varying between 4.69 and 4.71 kcal/mol (1639.69–1647.34 cm−1). Furthermore depending on the basis set, the ground state vibrational proton tunneling splitting, ΔEsplit, varies between 0.27 and 0.29 cm−1.