Thermal Decomposition Pathways and Rates for Silane, Chlorosilane, Dichlorosilane, and Trichlorosilane
Thermal Decomposition Pathways and Rates for Silane, Chlorosilane, Dichlorosilane, and Trichlorosilane
复制标题
DOI：
10.1021/jp003559u
复制
发表时间：
2001-02
影响因子：
2.9
通讯作者：
S. Walch;Christopher E. Dateo
中科院分区：
文献类型：
--
作者：
S. Walch;Christopher E. Dateo
对硅烷、氯硅烷、二氯硅烷和三氯硅烷的热分解进行了计算。在每种情况下，均使用 CASSCF/导数方法和 cc-pVDZ 基组来表征驻点几何形状和谐波频率。通过将使用 a-cc-pVTZ 基组的 CCSD(T) 结果与使用 MP2 级别的 a-cc-pVDZ、a-cc-pVTZ 和 a-cc-pVQZ 基组外推至基组极限相结合，获得了准确的能量学。使用传统的过渡态理论，利用几何、能量和谐波频率来获得速率常数。本工作中获得的势垒高度（kcal/mol）如下：SiH4→SiH2+H2（61.9）； SiClH3 → SiClH + H2 (66.7)； SiClH3 → SiH2 + HCl (76.9)； SiCl2H2 → SiCl2 + H2 (77.2)； SiCl2H2 → SiClH + HCl (74.8)； SiCl3H → SiCl2 + HCl (72.7)。计算出的势垒高度被认为精确到 1 kcal/mol 以内。本工作中获得的比率系数是公平考虑的...
Calculations have been carried out for the thermal decomposition of silane, chlorosilane, dichlorosilane, and trichlorosilane. In each case, the stationary point geometries and harmonic frequencies were characterized using CASSCF/derivative methods and the cc-pVDZ basis set. Accurate energetics were obtained by combining the CCSD(T) results using the a-cc-pVTZ basis set with an extrapolation to the basis set limit using the a-cc-pVDZ, a-cc-pVTZ, and a-cc-pVQZ basis sets at the MP2 level. The geometries, energetics, and harmonic frequencies were used to obtain rate constants using conventional transition state theory. The barrier heights obtained in the present work (kcal/mol) are the following: SiH4 → SiH2 + H2 (61.9); SiClH3 → SiClH + H2 (66.7); SiClH3 → SiH2 + HCl (76.9); SiCl2H2 → SiCl2 + H2 (77.2); SiCl2H2 → SiClH + HCl (74.8); SiCl3H → SiCl2 + HCl (72.7). The computed barrier heights are believed to be accurate to within 1 kcal/mol. The rate coefficients obtained in the present work are in fair acco...