On the stability of symmetric four-particle molecules

The stability of four-particle molecules m 1 + m 2 + m 3 − m 4 − with unit charges of particles is studied for different masses of the particles. It is shown that all molecules containing two like particles with masses m 3 = m 4 are stable against dissociation. Their stability results from the stability of symmetric molecules with m 1 = m 2 and m 3 = m 4 and from the stability of molecules with masses of particles m 3 = m 4 and m 1 = ∞ containing one infinitely heavy particle.