REDISTRIBUTION OF RESONANCE BONDS AND DYNAMICS OF 2-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.