Vibrational and rotational effects in the Cl+HOD↔HCl+OD reaction

Abstract

Quantum scattering calculations on the Cl+HODR⇌Cl+OD reaction have been performed at collisional energies up to 1.6 eV. The rotating bond approximation is used. In this method, the OD rotation and HCl vibration as well as the bending motion and OH local stretch of HOD are treated explicitly. Here, the theory is extended to account for thermal HOD reactant rotation. The potential energy surface used has accurate reactant and product rovibrational energy levels, correct bond dissociation energies, and a transition state geometry in accord with ab initio data. Mode selectivity is observed—HOD vibrational stretch energy enhances reaction more than vibrational bend energy. Translational energy enhances reaction more than vibrational stretch energy at low total energies, but not generally at higher total energies. Excitation of the local OH stretch in the reactant HOD produces vibrationally excited HCl product. The OD product rotation depends on the reactant HOD rovibrational state. The OD+HCl(v=0) reaction preferentially produces HOD in the vibrational ground state, while the OD+HCl(v=1) reaction preferentially produces HOD with one quantum of vibrational stretch energy. A calculated OH product rotational distribution for the Cl+H2O reaction agrees quite well with experiment.

Reaction dynamics calculations for the CN+H2→HCN+H reaction: Applications of the rotating-bond approximation

“…͑2͒ should be averaged by summing over angular configurations associated with in-plane and out-ofplane bending motions which are not included in the dynamical calculation, and by dividing by a weighted sum of initial H 2 rotational states. 21,22 This procedure is essentially the same as the ''rotationally averaged cross section'' proposed by Bowman. 1 However, this conversion has not been done in this work because we are interested in the qualitative behavior of mode specific dynamics in the CNϩH 2 reaction.…”

“…[19][20][21][22] In this theory, vibrational motion of H 2 and rotational motion of CN are treated explicitly in the dynamics. Since the methodology of the RBA has been well described in previous papers, [19][20][21][22] we present only a brief description that emphasizes the fourdimensional ͑RBA4D͒ treatment. In most of the applications of the RBA, the spectator vibrational motion is frozen during collision, which leads to a 3D scattering calculation.…”

Quantum dynamics of the O(3P)+CH4→OH+CH3 reaction: An application of the rotating bond umbrella model and spectral transform subspace iteration

“…This avenue of research was stimulated by papers by Sun and Bowman [22][23][24] and Brooks and Clary 25 10 years ago. In particular, the rotating bond approximation ͑RBA͒ of Clary [26][27][28] has been used frequently. The RBA includes nonlinear geometries and has been applied to many four-atomic and polyatomic reactions, see, e.g., Refs.…”

Quantum scattering calculations on the NH3+OH→NH2+H2O reaction

“…7,11,22 In the present paper the RBA is applied to the six-atom reaction NH 3 ϩOH→NH 2 ϩH 2 O. In the quantum scattering calculations, the NH 3 moiety is treated as a quasidiatom QH, where Q is a quasiatom with the mass of NH 2 .…”