MODEL OF THE CYCLIC TRANSITION-STATE FOR ALKYLPEROXY RADICAL ISOMERIZATION - CALCULATION OF PREEXPONENTIAL FACTORS

A model of the cyclic transition state for alkylperoxy radical isomeri zation ROO --> R'OOH is proposed. The frequencies of the C-H-O group o f the cyclic transition state are determined using the literature nb i nitio calculation data for isomerization of methylperoxy and ethylpero xy radicals that ensure the intramolecular H-atom transfer from the ca rbon atom to the oxygen atom. Preexponential factors of the rate const ants are calculated for the isomerization of different types (1.3, 1.4 , and 1.5). The calculation results are compared with the available ex perimental data and the values recommended by different authors.