Theoretical study on the structures, isomerization and stability of SiC4 isomers

• Published in: Theoretical chemistry accounts Vol. 126; no. 1-2; pp. 15 - 25
• Main Authors: Sun, Hao, Gong, Hongwei, Liu, Huiling, Wang, Fang, Pan, Xiumei, Su, Zhongmin, Sun, Chiachung, Wang, Rongshun, Huang, Xuri
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer-Verlag 01.05.2010
• Subjects: Atomic/Molecular Structure and Spectra; Chemistry; Chemistry and Materials Science; Inorganic Chemistry; Organic Chemistry; Physical Chemistry; Regular Article; Theoretical and Computational Chemistry; Potential energy surface; Stability; SiC; Isomer
• ISSN: 1432-881X; 1432-2234
• DOI: 10.1007/s00214-009-0646-5

The structures, energetics, dipole moments, vibrational spectra, rotational constants, and isomerization of singlet SiC 4 isomers were explored using ab initio methods. Five types of isomers, a total of 11 minima, connected by 11 interconversion transition states, were located on the potential energy surface at the MP2/6-311G(d, p) level. More accurate energies were obtained at the G3(MP2) level. With the highest isomerization barrier, a C2v tetra-angular cone possesses the largest kinetic stability. The lowest-lying structure, linear SiCCCC is also highly kinetically stabilized. Besides, D2d bicyclic c-Si(CC) 2 , C2v five-membered ring c-SiCCCC, another C2v tetra-angular cone isomer and C3v trigonal bipyramid isomer are also considered to be kinetically stable, because their isomerization barriers are all over 10 kcal/mol. Other isomers cannot be kinetically stabilized with considerably low isomerization barriers. Investigation on the vibrational spectra, dipole moments, and rotational constants for SiC 4 isomers are valuable for their detections in the interstellar space and laboratory.