Time-dependent quantum study of the kinetics of the H(2S) + FO(2II) → OH(2II) + F(2P) reaction

Wave packet calculations on nonadiabatic effects for the O(3P)+HF(1Σ+) reaction under hyperthermal conditions

We present wave packet calculations of total and state-to-state reaction probabilities and integral cross sections for the nonadiabatic dynamics of the O((3)P)+HF → F((2)P)+OH((2)Π) reaction at hyperthermal collision energies ranging from 1.2 to 2.4 eV. The validity of the centrifugal sudden approximation is discussed for the title reaction and a comprehensive investigation of the influence of nonadiabatic effects on the dynamics of this reactive system at high (hyperthermal) collision energies is presented. In general, nonadiabatic effects are negligible for averaged observables, such as total reaction probabilities and integral cross sections, but they are clearly observed in detailed observables such as rotationally state-resolved reaction probabilities. A critical discussion of nonadiabatic effects on the dynamics of the title reaction is carried out by comparing with the reverse reaction and the characteristics of the adiabatic and diabatic potential energy surfaces involved.

STATE-TO-STATE REACTION DYNAMICS OF THE D(H) + FO → OD(OH) + F REACTIONS ON THE LOWEST TWO TRIPLET STATES

Quasiclassical trajectory (QCT) calculations have been performed to investigate the reaction dynamics of the title reactions at a state-to-state level. The recently developed adiabatic potential energy surfaces (PESs) of the two triplet electronic states of 13A″ and 13A′ (Gómez-Carrasco S. et al., J Chem Phys121:4605, 2004; J Chem Phys123:114310, 2005) are employed in the present QCT calculations. Product vibrational and rotational state distributions have been calculated at three collision energies of 0.5, 0.7 and 0.9 eV. The product vibrational state distributions are found to be Gaussian distributions. Both the vibrational and rotational state distributions depend clearly on the isotope substitution, electronic PESs and collision energies. The observed phenomena are probably attributed to the competition of direct and indirect reactions.

Nonadiabatic state-to-state reactive collisions among open shell reactants with conical intersections: the OH((2)Pi) + F((2)P) example

Accurate wave packet calculations on the OH((2)Pi) + F((2)P) → O((3)P) + HF((1)Sigma(+)) reactive collisions are performed using a recently proposed coupled diabatic states. Adiabatic and nonadiabatic dynamics are compared in detail, analyzing the final state distribution of products. It is found that with the new surfaces a significant increase of the rate constant is obtained, with noticeable nonadiabatic effects. The inclusion of the spin-orbit splittings for the calculation of the electronic partition function produces an important increase of the reaction rate constants, yielding a rather good agreement with the experimental results. It is also concluded that spin-orbit couplings are also necessary in the entrance channel to describe this reaction.