Germylene energetics: spectroscopic constants and bond dissociation energies of GeX, GeX−, GeX+, GeX2, GeX2− and GeX2+ (X = F, Cl, Br and I)

Abstract

Ab initio investigation of the spectroscopic constants, bond dissociation energies of germanium monohalides, germanium dihalides and their ionic systems, viz. GeX, GeX⁻, GeX⁺, GeX₂, GeX₂⁻ and GeX₂⁺ (X = F, Cl, Br and I) have been carried out using correlation consistent triple-zeta basis sets for F and Cl and similar triple-zeta basis sets with RECPs for Ge, Br and I atoms. Geometry and frequency of all the neutral and ionic systems of germanium halides are obtained using MP2, CCSD(T) and QCISD(T) methods. The energetics are obtained at the CCSD(T)//MP2, QCISD(T)//MP2, CCSD(T) and QCISD(T) levels. Electron affinity (EA) and ionization potential (IP) of the monohalides and dihalides are reported to be consistent with the data available in literature. The bond dissociation energies (BDEs) to various dissociation asymptotes for most of the ionic systems are to be reported new in literature. The BDEs of the neutral germanium dihalides GeX₂ are calculated by using the BDEs of GeX₂⁻ and GeX₂⁺ ions and EA and IP of the associated neutral systems. A good agreement is found between the calculated values and the data wherever available. The BDEs of GeX₂ for higher halogen member are reported to be new in literature. The enthalpies of formation for atomization and ionization of the neutral GeX₂ dihalides are also reported here. The enthalpies of ionization are reported first time in literature and found consistent with other group IV dihalides. The reported molecular properties may be helpful to understand the chemistry involved in the plasma-assisted fabrication process of the Ge-based modern microelectronic devices, as well as will serve as a future reference.