Spin-flip reactions of Zr + C2H6 researched by relativistic density functional theory期刊界 All Journals 搜尽天下杂志传播学术成果专业期刊搜索期刊信息化学术搜索

Spin-flip reactions of Zr + C2H6 researched by relativistic density functional theory

Authors:

Yi Xiao Xian-Yang Chen Yi-Xiang Qiu Shu-Guang Wang

Institution:

1. School of Chemistry and Chemical Engineering, Shanghai Jiao Tong University, 200240, Shanghai, China

Abstract:

Density functional theory (DFT) with relativistic corrections of zero-order regular approximation (ZORA) has been applied to explore the reaction mechanisms of ethane dehydrogenation by Zr atom with triplet and singlet spin-states. Among the complicated minimum energy reaction path, the available states involves three transition states (TS), and four stationary states (1) to (4) and one intersystem crossing with spin-flip (marked by ?): ³Zr + C₂H₆ → ³Zr-CH₃-CH₃ (³ 1) → ³ TS _1/2 → ³ZrH-CH₂-CH₃ (³ 2) → ³ TS _2/3 ? ¹ZrH₂-CH₂ = CH₂ (¹ 3) → ¹ TS _3/4 → ¹ZrH₃-CH = CH₂ (¹ 4). The minimum energy crossing point is determined with the help of the DFT fractional-occupation-number (FON) approach. The spin inversion leads the reaction pathway transferring from the triplet potential energy surface (PES) to the singlet’s accompanying with the activation of the second C-H bond. The overall reaction is calculated to be exothermic by about 231 kJ mol^?1. Frequency and NBO analysis are also applied to confirm with the experimental observed data.

Reaction 3 Zr + C 2 H 6 → 3 ZrH ? CH 2 ? CH 3 ? 1 ZrH 2 ? CH 2 = CH 2 → 1 ZrH 3 ? CH = CH 2 $ {}^{\mathbf{3}}\mathrm{Zr}+{\mathrm{C}}_{\mathbf{2}}{\mathrm{H}}_{\mathbf{6}}{\to}^{\mathbf{3}}\mathrm{Zr}\mathrm{H}-{\mathrm{C}\mathrm{H}}_{\mathbf{2}}-{\mathrm{C}\mathrm{H}}_{\mathbf{3}}{\Rightarrow}^{\mathbf{1}}{\mathrm{ZrH}}_2-{\mathrm{C}\mathrm{H}}_2={\mathrm{C}\mathrm{H}}_2{\to}^{\mathbf{1}}{\mathrm{ZrH}}_{\mathbf{3}}-\mathrm{CH}={\mathrm{C}\mathrm{H}}_{\mathbf{2}} $ proceeds via spin-flip surface hopping over several transition states has been investigated. The minimum energy crossing point is determined with the help of the DFT fractional-occupation-number (FON) approach.

Keywords:

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