Dynamics of structural relaxation upon Rydberg excitation of an NO impurity in rare gas solid matrices

Abstract

We study the dynamics of structural relaxation, induced by excitation of an NO molecule, to its A 2 Σ + Rydberg state in rare gas (RG) solids. Classical molecular dynamics simulations were carried out to describe the dynamics of the cage, formed by RG atoms surrounding the NO molecule. The results show a behaviour characterized by an impulsive expansion of the cage radius at short times, followed by a complex oscillatory pattern around the average NO -RG distance of ~3. The size of the cage radius in the Rydberg state increases from ~5% (Xe) to ~25% (Ne) when compared with the initial cage radius. The experimental work showed a recurrence time of ~1.4 ps (Ne) and ~0.8 ps (Ar), while in our theoretical results we obtained ~2 ps (Ne) and 0.8 ps (Ar), which is in good agreement with experimental results. The molecular dynamics simulations of the higher shells reveal a high degree of directionality of the propagation of the deformation in the solids, except in the NO -Ne solid system. We explained the dependences of the different behaviour in each system.

Molecular dynamics simulations and hyperspherical mode analysis of NO in Kr crystals with the use of ab initio potential energy surfaces for the Kr‐NO complex

“…Motivated by these experimental results on doped‐RG solids, theoretical studies based on classical molecular dynamics (MD) simulations have been performed to get new and deeper insights into the dynamics of the structural relaxation. We can mention, for example, MD simulations of Hg‐doped Ar matrices 14 and NO‐doped Ar, Kr, and Xe matrices 15–21. These studies have provided a reasonable description of the experimental results for the Stokes shift and the bubble size 2, 11 and have also given a characterization of the ultrafast dynamics of the structural relaxation around the impurity after excitation.…”

“…The hyperspherical analysis is appropriate for this problem since it allows us to distinguish between the radial motion, due to the “breathing” mode of the whole system, and the overall angular motion, leaving unchanged the mean distance between the atoms, by means of the two term separation scheme named as Smith decomposition 26. Results are compared with former studies on NO doped Kr matrices 19–21, 24, 27 and to experimental data 2, 6, 9, 11.…”

An ab initio study of Xe–NO(X2II) and Xe–NO(A2Σ+) potential energy surfaces

“…In this respect, classical molecular dynamics simulations have been carried out to describe the dynamics of structural relaxation and energy redistribution in these systems, such as the dynamics of structural relaxation in NOdoped Ne, Ar, Kr and Xe solids upon Rydberg photoexcitation of the impurity [17,[41][42][43][44][45][46]. These studies have used isotropic potentials for the NO(X 2 )-RG interactions from the experimental results of Thuis et al [47] for RG = Ar, Kr, Xe and from reference [48] for RG = Ne.…”

Argon Solid Response upon Rydberg Photoexcitation of the NO Chromosphore: Case of Using ab Initio Potential Energy Surfaces and Comparison to Similar Studied Systems

“…Several works on molecular dynamics (MD) simulations of the structural relaxation of Rydberg excited NO-doped Ne, Ar, Kr, and Xe solids have been carried out. Primary, a group of these works used isotropic potentials. − The potential energy surfaces (PESs) for NO(X 2 Π)−RG interactions have been taken from the experimental results of Thuis et al for RG = Ar, Kr, Xe and from ref for RG = Ne. However, for the NO(A 2 Σ + )−RG (RG = Ne, Kr, Xe) interactions, several approximations have been used since no semiempirical intermolecular potential is available in the literature.…”