STABILITY OF COULOMB-SYSTEMS IN DEPENDENCE OF PARTICLE CHARGE

The stability of Coulomb systems as depending on the charges of the particles is investigated. It is shown that each stable system produces a region in which systems with varying charge remain stable; it is also shown that each stable system with only one coupled energy level produces a region in which such systems are unstable. The stability and instability regions for three-particle Coulomb systems are determined in an analytical form depending on the particle charges. The boundaries of the regions are calculated for systems obtained on variation of the charges of particles from an atomic ion H- (infinity) with an infinitely heavy nucleus, the mu+e-e- ion and positronium ion e-e-e+. The boundaries of the stability regions are calculated for systems obtained in a similar manner from the mesic molecular ion d+d+mu-, isotopic modifications of the hydrogen molecular ion p+p+e-, p+d+e- and d+d+e- and also from this ion with infinitely heavy H2+ (infinity) nuclei. In this case the motion of all particles in the system and relevant correlation and nonadiabaticity effects are taken into account. The limits of the critical charge Z(cr) and critical particle coupling parameter lambda-cr in the systems considered are calculated. For these systems the limits are obtained for the first time except for the case of the atomic ion H- (infinity). For H- (infinity) the two-sided boundaries of the critical nuclear charge found in the present study are much more exact than those determined in [11]. The result can be employed to analyzed the stability of various Coulomb systems and to investigate the convergence of perturbation theory with respect to the coupling parameter lambda for like charges in the systems.