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

Abstract

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 on quasimolecular optical transitions in hot dense plasma have renewed the interest to the concept in the recent years. The present review deals with highly charged quasimolecules and it is dedicated specifically to quasimolecules 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 be obtained straightforwardly in nonrelativistic case without any approximation that are typical for neutrals. Although the results obtained in the frame of the approach developed here are directly applicable to the case of single collisions or to low-density plasmas, they form a reasonable initial approximation for the problem of optical profiles in hot dense plasmas and can be regarded as a safe framework for qualitative discussions of profiles in those environments.

Асимптотически Запрещенные По Спину Квазимолекулярные Радиационные Переходы

“…К радиационным процессам при симметричных столкновениях можно отнести и процессы с участием ионов, например, перезарядку. В частности, резонансная перезарядка в основное состояние иона сопровождается квазимолекулярным радиационным переходом, вероятность которого обращается в ноль при больших расстояниях R [8,9]. О тематике запрещенных переходов в эксперименте.…”

Radiative transitions in quasi-molecules

“…The radiative transitions in the single-electron quasi-molecule Z 1 eZ 2 are of particular interest, because the dipole moments and terms that are necessary for calculating spectra can be determined exactly in the nonrelativistic approximation [22], which excludes the difficulties of quantum-chemical calculations typical of many-electron quasi-molecules. At the same time, the spectra of this quasi-molecule are important for the spectroscopy of hot plasma.…”

“…A specific feature of radiative transition is that its dipole moment is zero at large distances; therefore, it can also be assigned to asymptotically forbidden transitions. For example, the radiative transition in Z 1 eZ 2 quasi-molecules have been discussed in recent reviews [22,23].…”

Asymptotically spin forbidden quasimolecular radiative transitions (review)

“…Radiation processes in symmetric collisions can also include processes involving ions, such as charge exchange. In particular, resonant charge exchange to the ground state of ion is accompanied by a quasimolecular radiative transition, the probability of which goes to zero at large distances R [8,9].…”