Femtosecond real-time probing of reactions. VIII. The bimolecular reaction Br+I2

Abstract

In this paper, we discuss the experimental technique for real-time measurement of the lifetimes of the collision complex of bimolecular reactions. An application to the atom-molecule Br + I, reaction at two collision energies is made. Building on our earlier Communication [J. Chem. Phys. 95, 7763 ( 1991)], we report on the observed transients and lifetimes for the collision complex, the nature of the transition state, and the dynamics near threshold. Classical trajectory calculations provide a framework for deriving the global nature of the reactive potential energy surface, and for discussing the real-time, scattering, and asymptotic (product-state distribution) aspects of the dynamics. These experimental and theoretical results are compared with the extensive array of kinetic, crossed beam, and theoretical studies found in the literature for halogen radical-halogen molecule exchange reactions.

Nonadiabatic molecular dynamics simulations of the photofragmentation and geminate recombination dynamics in size-selected I2−⋅Arn cluster ions

“…7,11,[13][14][15][16][17][18][19] The more recent experiments involve the use of both photofragmentation 20,21 and ultrafast pump-probe techniques 22,23 and have been applied to investigate the X 2 Ϫ (XϭI,Br) photodissociation and cage recombination dynamics in size selected X 2 Ϫ •S n (SϭAr,CO 2 ) ionic molecular clusters. 20,24,25 I 2 Ϫ exhibits a strong absorption spectrum corresponding to an electronic excitation from the bound X, 2 ⌺ u,1/2 ϩ ground state to the repulsive AЈ, 2 ⌸ g,1/2 excited state 26 ͑see Fig.…”

Surface aligned photochemistry: Photodissociation of Cl2 and Cl2⋯Cl adsorbed on LiF(001)

“…Since trihalogen molecules have frequently been postulated as intermediates in chemical reactions, [39][40][41][42][43][44][45][46][47][48] we propose that the species giving rise to the fast Cl is the Cl 2¯C l(ad) complex formed at the cold surface as a result of prior partial photodissociation of Cl 2 (ad). A direct spectroscopic evidence for the Cl 2¯C l (Cl 3 ) complex has been provided recently.…”

How a collision complex forgets its origin: H3 +

“…ref. 14). (One has to find a reaction, which forms complexes only from an excited projectile or target, and monitor the products with the second laser pulse.)…”