The doublet potential energy surfaces of [Si, C, S]＋ and [Si, C, S]－ systems were investigated by the DFT, QCISD, and CCSD(T) methods. At the QCISD/6-311＋G(d) level, it is shown that a total of 3 minimum isomers are connected by 2 transitional states and 4 minimum isomers are connected by 2 transitional states for [Si, C, S]＋ and [Si, C, S]－ systems, respectively. Through an analysis of thermodynamic and kinetic stabilities, there is a linear doublet isomer [Si—C—S]＋ located as the stable isomer in [Si, C, S]＋ system. In doublet [Si, C, S]－ system, two stable isomers are located, which are a linear [Si—C—S]－ and a three-membered ring form c-[SiCS]－

Key words: theoretical study, [Si, C, S]＋, [Si, C, S]－, isomer, potential energy surface