Theoretical Studies of Photodissociation Dynamics in Large Clusters and in Solids
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The photodissociation of diatomic molecules such as CI2 and HI embedded in large clusters and in solid matrices of Ne, Ar and Xe is studied by classical trajectories. The clusters studied are of N≈ 102 to 103 atoms, the initial temperature in the calculations was 0°K. The methods used are: (1) Molecular Dynamics simulations including all particles; (2) A scheme which combines Molecular Dynamics for many particles with a harmonic treatment of atoms far from the reaction site. This study is the first simulation of reaction dynamics in solids. Specific results include: (i) The Cl2[Ne]N clusters lose several Ne atoms within <1 psec following photodissociation, while the corresponding Ar clusters have essentially infinite lifetimes. This is due to a shock wave generated by the photodissociation in the Ne case, while in the Ar cluster the energy rapidly randomizes. The behavior is dominated by mass ratios and potential range parameters; (ii) Recombination is incomplete in Cl2 [Ne]N. The CI atoms produced are trapped at interstitical sites within several Å of the photodissociation site; (iii) Comparison of theory and experiment for HI[Xe]N suggests that in low-energy photodissociation the H exit from the cage is entirely by tunneling.
KeywordsImpurity Molecule Molecular Reaction Dynamic Photodissociation Dynamics Infinite Lifetime Ground State Potential Energy Curve
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