Structures, relative stability and dissociation of [Si,N,C,O]^(2+) isomers  

作　　者：池玉娟 李泽生 于海涛 孙家钟 傅宏刚 

出　　处：《Science China Chemistry》2002年第6期561-569,共9页中国科学（化学英文版）

基　　金：This work was supported by the National Natural Science Foundation of China(Grant Nos.20171015,20171016);Science Foundation for Excellent Youths of Heilongjiang University(2002); and the Natural Science Foundation of Heilongjiang Province(Grant No.E0

摘　　要：Fifteen isomers of [Si,N,C,O]2+ system are obtained at UB3LYP/6-311G(d) and UCCSD(T)/6-311+G(2df) (single-point) levels. The analyses are made for predicting the structures of optimized isomers, while ionic fragments with lower energies are suggested. The calculated results indicate that linear isomer SiNCO2+(2Π) is thermodynamically the most stable species in [Si,N,C,O]2+ system, followed by linear SiOCN2+ (2Π), SiCNO2+ (2Π), and SiC(NO) (2A) with NCO three-membered ring. The order of stability of several kinetically stable isomers is SiNCO2> SiCNO2+ (2Π)>SiOCN2+>SiC(NO)2+>OSiNC2+ (2Π). The obtained results by analyzing the isomerizations and ionic fragment patterns show that the signal peaks of [Si,N,C,O]2+ are attributed to the contribution of linear SiNCO2+ species, which is metastable and can dissociate to the ionic fragments in the mass spectrometry experiments.Fifteen isomers of [Si,N,C,O]2+ system are obtained at UB3LYP/6-311G(d) and UCCSD(T)/6-311+G(2df) (single-point) levels. The analyses are made for predicting the structures of optimized isomers, while ionic fragments with lower energies are suggested. The calculated results indicate that linear isomer SiNCO2+(∏) is thermodynamically the most stable species in [Si,N,C,O]2+ system, followed by linear SiOCN2+ (∏), SiCNO2+ (∏), and SiC(NO) (2A″ ) with NCO three-membered ring. The order of stability of several kinetically stable isomers is SiNCO2 ＞ SiCNO2+ (NO)＞SiOCN2+ ＞ SiC(NO)2+＞OSiNC2+ (∏). The obtained results by analyzing the isomerizations and ionic fragment patterns show that the signal peaks of [Si,N,C,O]2+ are attributed to the contribution of linear SiNCO2+ species, which is metastable and can dissociate to the ionic fragments in the mass spectrometry experiments.

关 键 词：[Si N C O]2+ system  isomerization  stability  dissociation. 

分 类 号：O641[理学—物理化学]