Born-Oppenheimer molecular dynamics on the H(2)S + NO(3) reaction in the presence and absence of water: the kinetic isotope effect.
The chemical mechanism of the H(2)S + NO(3) reaction in the absence and presence of water molecules was investigated using the Born-Oppenheimer molecular dynamics. These calculations were performed to gain insight into the underlying chemical mechanism and to evaluate the kinetic isotope effect in the H(2)S + NO(3) and D(2)S + NO(3) reactions. When H(2)O interacts with NO(3), the rate coefficient of the H(2)S + NO(3) reaction is smaller than that for H(2)O interacting with H(2)S. Deuterium generally decreases the rate when D(2)O interacts with D(2)S but has no effect when D(2)O interacting with NO(3). When H(2)O or D(2)O interacts with NO(3), the yields are larger compared to those for the reactions (H(2)O)H(2)S + NO(3) and (D(2)O)H(2)S + NO(3). Furthermore, the average reaction times of the reactions H(2)S + NO(3)(H(2)O) and H(2)S + NO(3)(D(2)O) are shorter than those when H(2)O or D(2)O interacts with H(2)S. The (H(2)O)H(2)S + NO(3) reaction may occur via two possible pathways: the non-water-assisted and water-assisted hydrogen abstraction mechanisms. However, the H(2)S + NO(3)(H(2)O) reaction only happens via the non-water-assisted mechanism.
Scaldaferri
Maria Clara Leite
MC
Departamento de Química, Pontifícia Universidade Católica do Rio de Janeiro, RJ Brazil.
Pimentel
Andre Silva
AS