Theoretical investigation on structures, stability and properties of [P, X, Y] (X=C, Si; Y = O, S) isomers

Abstract

The structures, energetics and stability of the [P, X, Y] (X = C, Si; Y = O, S) radicals are explored by means of the density functional theory and ab initio levels. Seventeen [P, X, Y] isomers and 14 interconversion transition states are obtained at the B3LYP/6-311G(d) level. At the CCSD(T)/6-311 + G(2df)//QCISD/6-311G(d) + ZPVE level, the lowest-lying isomers are the linear PCO 1a (0.0 kcal/mol), PCS 1b (0.0) and the three-membered ring cPSiO 1c (0.0), cPSiS 1d (0.0) on their respective potential energy surfaces. These four isomers exhibit considerably not only thermodynamic but also kinetic stabilities. Additionally, the cyclic cPCS 2b (32.8) and linear PSiS 2d (18.6) possess also high kinetic stability. All of six isomers 1a, 1b, 2b, 1c, 1d and 2d are considerably stabilized by a barrier of at least 20 kcal/mol, and may be detected in the laboratory or interstellar space. Their valence bond structures and possible formation strategies in the laboratory and space are discussed in detail. Finally, the similarities and discrepancies on structures and stabilities between [P, X, Y] (X = C, Si; Y = O, S) isomers are compared. These predicted results are highly expected to be informative for the future identification of [P, X, Y] (X = C, Si; Y = O, S) in the laboratory and space.

Keywords:

• potential energy surface
• isomer
• structure
• stability
• interstellar

Acknowledgements

This work was supported in China by NSFC (21103065, 21073075 and 21173097), National Basic Research Program of China (973 Program) (2012CB932800), and the Ministry of Education of China (20110061120024 and 20100061110046), G. T. Yu and W. Chen thank the equipment funds (450091105163 and 450091105164) and funds (450060481347, 450080011085 and 450080011084) from Jilin University. We thank the High Performance Computing Center (HPCC) of Jilin University for supercomputer time.