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

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 -3.9 A for NO(A 2 Σ + )-Ne, ∼4 A for NO(A 2 Σ + )-Ar, -4.24 A for NO(A 2 Σ + )-Kr, and ∼4.55 A for NO(A 2 Σ + )-Xe. 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.