Positronium is a short-lived bound state with lifetime approximately $$10^{-9}\ \text{s}$$ of an electron and a positron, a positively charged particle with mass and charge equal in magnitude to an electron, revolving round their common centre of mass. If $$E_0$$, $$v_0$$ and $$a_0$$ are respectively the ground state energy, the orbital speed of electron in first orbit and the radius of the first $$n=1$$ Bohr orbit for Hydrogen atom, the corresponding quantities $$E$$, $$v$$ and $$a$$ for positronium are