Optical Transitions and Charge-Exchange in Highly Charged Quasi-Molecules

The interaction between quasimolecular states produces not only nonadiabatic transitions but also some exotic features in the wings of the spectral profiles emitted by the ions in collision. Although this concept has been fruitfully used for neutral species, some new highlighted experimental data onquasimolecular optical transitions in hot dense plasma have renewed the interest to the concept inthe recent years. The present review deals with highly charged quasimolecules and it is dedicated specifically toquasimolecules formed by two bare nuclei and one bound electron. The reason for this choice is that,for such quasimolecules, the energy terms and the dipole moments of the optical transitions can beobtained straightforwardly in nonrelativistic case without any approximation that are typical forneutrals. Although the results obtained in the frame of the approach developed here are directlyapplicable to the case of single collisions or to low-density plasmas, they form a reasonable initialapproximation for the problem of optical profiles in hot dense plasmas and can be regarded as a safeframework for qualitative discussions of profiles in those environments