Rotational energy relaxation quantum dynamics of a diatomic molecule in a superfluid helium nanodroplet and study of the hydrogen isotopes case

Abstract

Rotational relaxation in a 4He superfluid nanodroplet is studied adapting a quantum approach recently proposed by us. In the first theoretical study on this problem several isotopes of H2 are examined (cascade mechanism, time scale of ns, etc.).

Rotational coherence spectroscopy of molecules in helium nanodroplets: Reconciling the time and the frequency domains

“…These two discrepancies between the measurements and simulations indicate that some of the rotational states excited by the alignment pulse decay on the time-scale of the measurements, i.e. that the alignment dynamics is also influenced by lifetime (homogenous) broadening [3,32]. This is likely also the case for OCS and CS 2 but measurement for longer times would have been needed to observe a similar decay of cos 2 θ 2D (t).…”

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

“…200 This method has been used recently to model rotational and vibrational energy relaxation in a diatomic molecule hosted in a helium droplet. 201,202 9.2 A non-statistical multi-member Ca/N 2 O chemiluminescence reaction within argon clusters and helium nanodroplets A historical perspective on the Ca/N 2 O system. Gas phase reactions of metal atoms with oxidant molecules have attracted a considerable interest in the 1970s and 1980s.…”

“…200 This method has been used recently to model rotational and vibrational energy relaxation in a diatomic molecule hosted in a helium droplet. 201,202…”