Redistribution of Resonance Bonds and Dynamics of Two‐Center Self‐Trapping in Rare‐Gas Crystals

It is shown that in the process of the exciton two‐center self‐trapping the resonance bonds generating a free exciton state are redistributed so that the total resonance contribution to the energy increases. 50% of the electronic excitation is concentrated inside a two‐center quasimolecule close to the self‐trapping threshold. The rest is distributed in neighbouring atoms, resulting in a generation of weaker extrinsic bonds along with the intermolecular resonance one. The attendant deformation of the molecular term produces a decrease in the self‐trapping barrier and an appreciable increase in its transparency.