title: Computational studies on metathetical and redox processes of HOCl in the gas phase: (II) reactions with ClO(x) (x = 1-4).
abstract: The reactions of HOCl + ClO(x) (x = 1-4) have been studied theoretically by ab initio quantum chemical and statistical mechanical methods. The structures of reactants, intermediates, products, and transition states were optimized at the MPW1PW91/6-311+G(3df,2p) level of theory, and the potential energy surface of each reaction was refined at the G2M and CCSD(T)/6-311+G(3df,2p) levels of theory. The most favorable reaction channels are predicted to be Cl-abstraction in HOCl + ClO with a barrier of 18.5 kcal/mol and H abstraction in HOCl + OClO with a barrier of 23.9 kcal/mol. In the HOCl + ClO(3) reaction both processes can occur; the barriers of Cl and H abstraction are 16.4 and 17.1 kcal/mol, respectively. In the HOCl + ClO(4) reaction, the H abstraction transition state lies below that of the reactants by 1.4 kcal/mol. The rate constants for all low barrier channels have been calculated in the temperature range 200-3000 K by statistical theory. In addition, the rate constant for the reverse of the HOCl + ClO reaction, Cl(2)O + OH --> HOCl + ClO, has been predicted; the result is in good agreement with the bulk of available experimental data.
authors.affiliation: Department of Chemistry, Emory University, Atlanta, Georgia 30322, USA.
authors.forename: Z F
authors.initials: ZF
authors.lastname: Xu
authors.forename: M C
authors.initials: MC
authors.lastname: Lin