Structures and Energetics of E2H3 + (E = As, Sb, and Bi) Cations

• Published in: The journal of physical chemistry. A, Molecules, spectroscopy, kinetics, environment, & general theory Molecules, spectroscopy, kinetics, environment, & general theory, 2024-01, Vol.128 (3), p.563-571
• Main Authors: Xia, Shu-Hua, He, Jihuan, Liu, Zhuoqun, Liu, Yunhan, Zhang, Yan, Xie, Yaoming, Lahm, Mitchell E., Robinson, Gregory H., Schaefer, Henry F.
• Format: Article
• Language: English
• Subjects: A: Structure, Spectroscopy, and Reactivity of Molecules and Clusters
• ISSN: 1089-5639; 1520-5215; 1520-5215
• DOI: 10.1021/acs.jpca.3c05945

E2H2 (E = As, Sb, Bi) structures involving multiple bonds have attracted much attention recently. The E2H3 + cations (protonated E2H2) are predicted to be viable with substantial proton affinities (>180 kcal/mol). Herein, the bonding characters and energetics of a number of E2H3 + isomers are explored through CCSD­(T) and DFT methods. For the As2H3 + system, the CCSD­(T)/cc-pVQZ-PP method predicts that the vinylidene-like structure lies lowest in energy, with the trans and cis isomers higher by 6.7 and 9.3 kcal/mol, respectively. However, for Sb2H3 + and Bi2H3 + systems, the trans isomer is the global minimum, while the energies of the cis and vinylidene-like structures are higher, respectively, by 2.0 and 2.4 kcal/mol for Sb2H3 + and 1.6 and 15.0 kcal/mol for Bi2H3 +. Thus, the vinyledene-like structure is the lowest energy for the arsenic system but only a transition state of the bismuth system. With permanent dipole moments, all minima may be observable in microwave experiments. Besides, we have also obtained transition states and planar-cis structures with higher energies. The current results should provide new insights into the various isomers and provide a number of predictions for future experiments.