Ar ··· I 2 : A model system for complex dynamics

Abstract

We review spectroscopic and photodissociation dynamical studies in the region of the B ← X transition of the Ar ... I 2 Van der Waals complex, both below and above the dissociation limit of the B(3 Π 0 + u) state. This very simple system constitutes a prototype for a wide range of molecular processes: vibrational predissociation involving intramolecular vibrational relaxation, electronic predissociation, cage effect... Each of these processes has been or still is the subject of differing interpretations: intramolecular vibrational relaxation involved in the vibrational predissociation of this system can be in the sparse or statistical regime, vibrational and electronic predissociation are in competition, and a direct, ballistic interpretation of the cage effect as well as a nonadiabatic one have been proposed. The study of the dependence of these dynamical processes on the relative orientation of the two partners of the complex (stereodynamics) is made possible by the coexistence of two stable Ar ... I 2 (X) isomers. Experimental as well as theoretical results are reviewed. Experiments range from frequency-resolved to time-dependent studies, including the determination of final state distributions. Theoretical studies involve potential energy surface calculations for several electronic states of the complex and their couplings, and adiabatic as well as nonadiabatic dynamical simulations.

Communications: A model study on the electronic predissociation of the NeBr2 van der Waals complex

“…9 This functional form fits very well the available ab initio calculations obtained for Ne-Cl 2 . 12 The B / C͑1 u ͒ coupling presents a different angular dependence ͑see factor.…”

“…With the total lifetimes, it would possible to assign the origin of the oscillations of the VP/EP relative efficiency measured by Burke and Klemperer, 3 for which there is still some controversy. 9 In addition, a similar study for Ne 2 Br 2 would be interesting since the EP rates scale quadratically while VP rates should scale approximately linearly with the number of Ne atoms. In this last case, if we consider that the Ne 2 Br 2 has a larger binding energy, the available kinetic energy decreases.…”

“…This was later confirmed by full quantum wave packet calculations 7,8 on the competition between VP and EP dynamics, as recently reviewed. 9 Thus the details of the competition between VP and EP in ArI 2 remain an open problem.…”

NeCl2 and ArCl2: Transition from Direct Vibrational Predissociation to Intramolecular Vibrational Relaxation and Electronic Nonadiabatic Effects

“…18 The dependence on R is as suggested by the ab initio calculations and the assumed constant dependence with r is consistent with a Laundau-Zener type process. 51 The values of the parameters are again obtained from fits to the ab initio calculations on the complex: ∆ ) 200 cm -1 (600), F e ) 3.6 (3.6) Å, and ) 2.8 (2.5) Å -1 for the Ne (Ar) complex.…”

Theoretical study of the structures, stabilities, and electronic properties of Na 2+ Xen (n = 1–6) clusters

“…Special intense interest is put on to the study of the clusters involving helium and other noble gas atoms as components. The rare gas clusters, especially those involving helium atoms, represent an ideal testing ground for many computational approaches [1][2][3][4][5], because the accurate knowledge of the relevant intermolecular forces between the solvent atoms and the dopants present in the cluster is an important prerequisite for the structural calculations and therefore fairly simple components provide ideal model systems for the analysis of the influence of intermolecular interactions on the clusters properties [6][7][8]. The structures and stability of atoms and diatomic molecules embedding in rare gas clusters have been extensively investigated by several experimental and theoretical works, because doped noble gas clusters present some additional interesting features, like the rapid heat transport generated inside the complex to the surface.…”