Hydrogen substituted by helium(+): Theoretical investigations on the structures and stabilities of He₂O²⁺, He₂N ²⁺, and He₂C²⁺

Theoretical studies of the structures and stabilities of the title compounds with respect to their dissociation reactions are reported at the MP4(SDTQ)/6-311G(2df,2pd)//MP2/6-31G(d,p) + zero point energy level of theory which shows that He₂O²⁺ (¹A₁) and He₂C²⁺ (³B₁) exhibit short, strong bonds, while He₂N²⁺ (²B₁) and He₂C²⁺ (¹A₁) are found to have comparatively long, weak bonds; He₂C²⁺ (¹A ₁) is predicted to be stable towards dissociation, while the other three dicationic species are energetically unstable.