The medium response to an impulsive redistribution of charge in solid argon: Molecular dynamics simulations and normal mode analysis

Abstract

Articles you may be interested inNormal and hyperspherical mode analysis of NO-doped Kr crystals upon Rydberg excitation of the impurity Structural dynamics in quantum solids. I. Steady-state spectroscopy of the electronic bubble in solid hydrogens Excitation of the A(3s) Rydberg state of NO leads to an extensive rearrangement of the environment, which we have investigated by classical molecular dynamics simulations and normal mode analysis, using pair potentials from the literature. We find that the medium response is independent of the details at long range of the excited state NO A-Ar potential, stressing the fact that it is mainly driven by the short range repulsive forces between the Rydberg electron and the matrix atoms. We establish the inertial character of the first shell response in the initial 100-150 fs after excitation, as the next shells are silent over this time scale. The expansion of the first shell at early times, induces the propagation of a supersonic wave along the ͑011͒ axis of the crystal, which define 12 linear chains of atoms with the impurity. The early time response is followed by vibrational coherences with a complex behavior. The normal modes analysis of the crystal shell by shell shows good agreement with the power spectra of the MD trajectories. It allows us to identify the most significant modes in the medium response. Overall, the dynamics of the system may be regarded as that of a NOAr 12 supermolecule, embedded in an Ar lattice and undergoing vibrational energy redistribution.

Atomic and molecular defects in solid 4He

“…Calculations [293,294] show that this relatively small molecule occupies a substitution site in the matrix, in the same way as alkali and noble metal atoms do. The molecular orbital of the lowest excited state A 2 Σ + is nearly spherical and its repulsive interaction with the surrounding rare gas atoms leads to a symmetric expansion of the cage that closely resembles the atomic bubble in condensed He.…”

Dynamics of excited tetrakis(dimethylamino)ethylene solvated by argon atoms

“…Still considering analogies, the deforming TDMAE molecule plays a role comparable to that of an expanding electronic bubble in solid argon [60].…”

“…close to that found for the aniline + -Ar interaction (520 cm −1 [50,51]). With this value, the total solvation energy of the TDMAE + (Ar) 60 cluster ion is 33,000 cm −1 ≈ 4.1 eV, still assuming that 20 argon atoms are present in the first solvation shell.…”

“…With these estimates of the TDMAE + (Ar) 60 and TDMAE(Ar) 60 solvation energies, the adiabatic ionisation potential of TDMAE(Ar) 60 falls from 5.4 eV for the free TD-MAE molecule [52] down to 4.8 eV. The latter value is consistent with the fact that almost no cluster ions are observed with the sole pump laser exciting the cluster beam, an indication that the ionisation energy of the cluster is not significantly smaller than the energy of the 266 nm photons (4.7 eV).…”

“…However, a parallel can be made with the mechanism by which an electronic bubble develops in response to the excitation of the A(3sσ) Rydberg orbital of NO within an argon matrix [60]. When considering the early dynamics of the electronic bubble in solid argon: i) only the first shell responds to the electronic excitation during the first 100 fs following the NO excitation; ii) the expansion of the first shell drains 0.33 eV of the available energy; iii) the position correlation function of the first shell atoms has a half width of 110 fs.…”