Theoretical investigation of the reaction of CN with OCS

The reaction of CN radical with OCS has been studied theoretically using an initio MO method. Six possible product channels have been found. For these reaction channels, the structure parameters, vibrational frequencies and energies for each stationary point have been calculated using G2MP2 method, and the corresponding reaction mechanism has been given by the potential energy surface which is drawn according to the relative energies. Using Eyring transition state theory with Wigner correction, the activation thermodynamic data, rate constant and frequency factors for the reaction channel (1) of producing CO + NCS have been given at the temperature of 200-2000 K and standard pressure. The resulting TST-based modified Arrhenius expression is k(200-2000 K) = 4.0749 X 10(-10)T(1.38) exp(-3648.2/T) cm(3) molecule(-1) s(-1). The results show that the reaction channel (1) is the main reaction channel in the reaction of CN with OCS, and that it is not only spontaneous but also easy to take place kinetically. (c) 2005 Elsevier B.V. All rights reserved.