Properties of the boundSstates (L=0) in Coulomb three-body systems with unit charges

Various energetic, geometric, and other properties for the ground and first vibrationally excited S states (L=0) of Coulomb three-body systems having unit charges are obtained by means of accurate exponential wave functions. The mass dependence of the properties for these systems has a relatively smooth form for the ground states. The results presented should be useful as a basis for further investigation of these three-body systems. The prethreshold (weakly bound) exotic nonsymmetric systems (d⁺{t}⁺p^-, μ⁺{{{π}}}⁺μ^-, and μ⁺{{{π}}}⁺π^-) considered have sharp cluster structures, i.e., the lighter positive ion moves in the field of the neutral pair (e.g., d⁺ in d⁺{t}⁺p^- moves in the field of t⁺{p}^{{{-}}}$ ).