【摘要】 在CCSD(T) /6 - 311G(2df) //B3LYP/6 - 311G(d)水平上对SiC2 S的各种可能异构体进行了研究 ,得到了其几何构型、精确能量和红外光谱 .结果表明 :SiC2 S有 8个稳定的异构体 ,能量最低的是直线型 ,电子态为1∑的SiCCP 1,其次是C2v对称性的S -cSiCC 5 ,第三稳定的是直线型1∑电子态异构体SSiCC 2 ,第四稳定的是具有CC桥键C2v对称性的长菱形结构的cCSiCS 7.更多还原

【Abstract】 The structures, energetics and vibrational frequencies of various SiC 2S isomers are investigated by means of the CCSD(T)/6-311G(2 df )//B3LYP/6-311G( d ) method. It is shown that eight isomers are obtained with all real frequencies as local minima. The global minima is a linear structure 1 with C≡C bonding followed by a second low-lying isomer 5 with SiCC three-member cycle with exocyclic SiS bonding. The third low energy isomer is linear SSiCC 2 with SSi and CC triple bonding, respectively. The fourth is a rhomboidal structure with C 2v symmetry with CC cross bonding and identical two SiC and two SC peripheral bonding, respectively. The structural discrepancies between SiC 2S and analogous molecules C 3O and C 3S are compared and discussed.更多还原