Butterfly, Vinylidene‐Like, Monobridged and Trans Structures of Si ₂ H ₂ ⁺ : Comparison to the Well‐Characterized Neutral Si ₂ H ₂

This paper investigates four of the constitutional isomers Si2H2+, namely butterfly, vinylidene-like, monobridged, and trans structures. These isomer geometries were all studied using CCSD(T) method with basis sets as large cc-pV5Z. Higher level methods CCSDT CCSDT(Q) used for final energetics. It is found that butterfly has lowest energy, followed by vinylidene-like monobridged structures; structure highest energy four. All structures compared their neutral counterparts. Partial charges are computed it share positive charge between silicon atoms. NBO analysis shows cation Si−Si bond order reduced 0.5 relative to versions same in case monobridged; 0.6 isomer. Vibrational frequencies, infrared intensities, dipole moments predicted encourage spectroscopic identification Si2H2+.