Direct ab initio study on the rate constants of radical C-2(A(3)Pi(u))+C3H8 reaction
The mechanism and kinetics of the radical C-3(2) + C3H8 reaction have been investigated theoretically by direct ab initio kinetics over a wide temperature range. The potential energy surfaces have been constructed at the CCSD(T)/B3//UMP2/B1 levels of theory. The electron transfer was also analyzed by quasi-restricted orbital (QRO) in detail. It was shown that all these channels proceed exclusively via hydrogen abstraction. The overall ICVT/SCT rate constants are in agreement with the available experimental results. The prediction shows that the secondary hydrogen of C3H8 abstraction by C-3(2) radical is the major pathway at low temperatures (below 700 K), while as the temperature increases, the primary hydrogen of C3H8 abstraction becomes more important and more favorable. A negative temperature dependence of the rate constants for the reaction of C-3(2) + C3H8 was observed. The three-(k (3)) and four-parameter (k (4)) rate-temperature expressions were also provided within 243-2000 K to facilitate future experimental studies.
rate constant c-2 chemical kinetics variational transition-state theory