Quantum–classical approach to the reaction dynamics in a superfluid helium nanodroplet. The Ne₂ dimer and Ne–Ne adduct formation reaction Ne + Ne-doped nanodroplet

Abstract

The Ne + Ne@(4He)N reaction dynamics was studied using a quantum–classical approach. The angular momentum plays a critical role: the Ne–Ne adduct formation dominates the reactivity (instead of the Ne2 dimer) and quantized vortices are produced.

Quantum dynamics of the Br2 (B-excited state) photodissociation in superfluid helium nanodroplets: importance of the recombination process

“…In this method, which has been previously proposed by us and applied to the related Cl 2 case, 25,26 the helium atoms are described by means of the mean field TDDFT method and the molecule is described using a time dependent quantum wave packet (WP). Besides, the common so-called Orsay-Trento (OT) phenomenological density functional (T = 0 K) 42 , including some reasonable and commonly used approximations (the backflow term and the non-local contribution to the helium correlation energy have not been considered), [25][26][27][29][30][31][32][33][34][35][43][44][45] has been used to account for the helium.…”

“…This work has been carried out employing a quantum hybrid method proposed 25 and previously applied by us (with some modifications when needed) to investigate the dynamics of several physicochemical problems involving ( 4 He) N and atoms or diatomic molecules (photodissociation, [25][26][27] atom capture, 28,29 van der Waals reaction, 30,31 vibrational relaxation, 32,33 rotational relaxation 34 and helium nanodroplet relaxation 35 ). Therefore, time dependent density functional theory (TDDFT) and standard quantum mechanics have been used to describe helium and the Br 2 molecule, respectively, analogously as in the case of the Cl 2 (B) photodissociation.…”

Reaction dynamics within a cluster environment

“…[67][68][69] Subsequent formation of a rare gas dimer within the nanodroplet has been modelled also, both in full quantum and a hybrid quantum (helium)/classical (rare gas) approaches. 70,71 Helium density waves (possibly carrying vortices), which are produced by the pick-up of the Ne atoms, were shown to drive the Ne movements within the droplet and control their association as dimer. Similar calculations are also available for the pick-up of a Cs atom.…”

A Path Integral Molecular Dynamics Simulation of a Harpoon-Type Redox Reaction in a Helium Nanodroplet

“…Among them, density functional theory applied to bosonic helium droplets, which implicitly incorporates the helium superfluidity, and where the dynamics are real-time [ 26 ]. The capture of one Ar atom [ 27 ] or up to six Ar atoms [ 28 ], and the formation of Ne dimers [ 29 ] or Ne-Ne adducts [ 30 ] in HNDs were recently studied using this methodology. In turn, and including explicitly the temperature, path integral Monte Carlo (PIMC) techniques [ 31 , 32 ] constitute an efficient alternative to study energies and equilibrium structures of different species attached to bosonic helium droplets, see for instance the studies on alkali dimers, Cs [ 33 ] and Rb [ 34 , 35 , 36 ] or on coronene [ 37 , 38 ] and on lithium ions [ 39 ].…”