Quantum interferences in the photodissociation of Cl2(B) in superfluid helium nanodroplets (4He)N

Arnau Vilà,Ricardo Mayol,Miguel González

doi:10.1039/c5cp03575a

Abstract

Quantum interferences are probably one of the most fascinating phenomena in chemical physics and, particularly, in reaction dynamics, where they are often very elusive from an experimental perspective. Here, we have theoretically investigated, using a hybrid method recently proposed by us, the dynamics of the formation of confinement quantum interferences in the photodissociation of a Cl2 molecule (B ← X electronic excitation) embedded in a superfluid helium nanodroplet of different sizes (50-500 (4)He atoms), which is to the best of our knowledge the first time that this type of interference is described in reaction dynamics. Thus, we have widely extended a recent contribution of our group, where interferences were not the main target, identifying the way they are formed and lead to the production of strongly oscillating velocity distributions in the Cl dissociating atoms, and also paying attention to the energy transfer processes involved. This probably corresponds to a rather general behavior in the photodissociation of molecules in helium nanodroplets. We hope that the present study will encourage the experimentalists to investigate this captivating phenomenon, although the technical difficulties involved are very high.

Highlights

From a chemical point of view, the research activity developed to date on the chemical reactivity in helium nanodroplets has been important, its intensity is not comparable to the effort carried out in the context of the studies of the physical type
In addition to our recent paper[4] and the present work on the title system, only one study on reaction dynamics could be found in the literature,[10] which is dedicated to the same problem examined here, but considers both a very different approach and strongly diverse physical conditions
The present study extends and complements our recent investigation on the photodissociation of homonuclear diatomic molecules in superfluid helium nanodroplets (T = 0.37 K), where the theoretical method proposed by us was applied for the first time to the photodissociation of a Cl2 excited embedded molecule (B ’ X electronic transition): Cl2(X)@(4He)N + hn - [Cl2(B)@(4He)N]* - Cl(2P3/2) + Cl(2P1/2) + [(4He)N0]* + (N–N0) 4He, l E 400 nm (3.10 eV),[12] where the term (N–N0) 4He merely reflects the total number of vaporized He atoms with N maximum = 500 (Fig. 1)

Summary

Introduction

From a chemical point of view, the research activity developed to date on the chemical reactivity in helium nanodroplets has been important (see, e.g., ref. 3, 4, and the references cited therein), its intensity is not comparable to the effort carried out in the context of the studies of the physical type. From a chemical point of view, the research activity developed to date on the chemical reactivity in helium nanodroplets has been important 3, 4, and the references cited therein), its intensity is not comparable to the effort carried out in the context of the studies of the physical type It appears that the chemical interest in these low temperature fluid systems has increased significantly, and this probably occurs thanks to the new possibilities offered by them in the chemical synthesis of novel chemical species.

Methods

Results

Conclusion