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采用从头算的单双取代的二次组态相互作用方法及耦合簇理论对SiF2自由基的基态进行结构优化, 发现用单双取代的二次组态相互作用方法配有基组6-311G(2df)计算得到的结构参数、谐振频率、离解能及力常数与实验值最接近并优于文献值. 借助多体项展式理论导出SiF2自由基的势能函数并绘制了等值势能图. SiF2自由基对称伸缩振动和旋转势能图显示: 在SiF+F →SiF2反应通道上有鞍点出现, F原子需要越过4.38 eV的能垒才能生成稳定的SiF2自由基; 只能通过SiF+F→SiF2两个等价的通道才能生成稳定的SiF2 自由基, 并且该反应是有阈能的吸热反应.The ab initio configuration interaction method and coupled-cluster theory have been used to optimize the possible ground-state structures of SiF2. The method QCISD/6-311G(2df) is most suitable for the calculation of SiF2 by comparing the experimental value and the calculated value; and the calculated equilibrium structure, harmonic frequency, dissociation energy, force-constant are in good agreement with the experimental data. The potential energy functions of SiF2 have been derived from the many-body expansion theory. In the symmetry of stretching vibration and rotation potential energy diagram of SiF2, there is a saddle point in the reaction kinetics SiF+F→SiF2. A stable SiF2 molecule could be formed when F atom with an energy surpassing 4.38 eV. These are completely reported so far as we know for the first time. In addition, it is found that a stable SiF2 molecule could be formed through two equivalent channels of SiF+F→SiF2. And the reaction is endothermic with a threshold energy.
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Keywords:
- SiF2 /
- ab initio /
- potential energy curve
[1] Johns J W C, Chantry G W, Barrow R F 1958 Trans. Faraday Soc. 54 1589
[2] Rao V M, Curl Jr R F, Timms Peter L 1965 J. Chem. Phys. 43 2557
[3] Dixon R N, Hallé M 1970 J. Mole. Spectrosc. 36 192
[4] Colvin M E, Grev R S, Schaefer Ⅲ H F, Bicerano J 1983 Chem. Phys. Lett. 99 399
[5] Johnson Ⅲ R D, Hudgens J W, Ashfold M N R 1996 Chem. Phys. Lett. 261 474
[6] Knizikevičius R 2005 Chem. Phys. Lett. 410 177
[7] Rao V M, Curl Jr R F 1966 J. Chem. Phys. 45 2032
[8] Khanna V M, Hauge R, Curl Jr R F, Margrave J L 1967 J. Chem. Phys. 47 5031
[9] Rao D R 1970 J. Mole. Spectrosc. 34 284
[10] Gole James L, Hauge Robert H, Margrave J L, Hastie J W 1972 J. Mole. Spectrosc. 43 441
[11] Caldow G L, Deeley C M, Turner P H, Mills I M 1981 Chem. Phys. Lett. 82 434
[12] Cai Z L, Bai J L 1993 Chem. Phys. 178 215
[13] Hebner G A 2002 Appl. Surf. Sci. 192 161
[14] Zhao J, Cheng X L, Yang X D, Zhu Z H 2009 Acta Phys. Sin. 58 5280 (in Chinese) [赵俊, 程新路, 杨向东, 朱正和 2009 58 5280]
[15] Chase M W, Davies C A, Downey J R 1985 J. Phys. Chem. Ref. Data 14 (Suppl. 1) 553
[16] Zhu Z H, Yu H G 1997 Molecular Structure and Molecular Potential Energy Function (Beijing: Science Press) (in Chinese) [朱正和, 俞华根 1997 分子结构和势能函数 (北京: 科学出版社)]
[17] Jan H, Zdenek H, Suehiro I 1999 Int. J. Mass. Spectrom. 192 165
[18] Han X Q, Xiao X J, Liu Y F 2011 J. Atom. Mol. Phys. 28 195 (in Chinese) [韩晓琴, 肖夏杰, 刘玉芳 2011 原子与分子 28 195]
[19] Han X Q, Xiao X J, Liu Y F 2013 Acta Phys. Sin. 62 193101 (in Chinese) [韩晓琴, 肖夏杰, 刘玉芳 2013 62 193101]
[20] Zeng H, Zhao J 2014 Acta Phys. Sin. 63 063101 (in Chinese) [曾晖, 赵俊 2014 63 063101]
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[1] Johns J W C, Chantry G W, Barrow R F 1958 Trans. Faraday Soc. 54 1589
[2] Rao V M, Curl Jr R F, Timms Peter L 1965 J. Chem. Phys. 43 2557
[3] Dixon R N, Hallé M 1970 J. Mole. Spectrosc. 36 192
[4] Colvin M E, Grev R S, Schaefer Ⅲ H F, Bicerano J 1983 Chem. Phys. Lett. 99 399
[5] Johnson Ⅲ R D, Hudgens J W, Ashfold M N R 1996 Chem. Phys. Lett. 261 474
[6] Knizikevičius R 2005 Chem. Phys. Lett. 410 177
[7] Rao V M, Curl Jr R F 1966 J. Chem. Phys. 45 2032
[8] Khanna V M, Hauge R, Curl Jr R F, Margrave J L 1967 J. Chem. Phys. 47 5031
[9] Rao D R 1970 J. Mole. Spectrosc. 34 284
[10] Gole James L, Hauge Robert H, Margrave J L, Hastie J W 1972 J. Mole. Spectrosc. 43 441
[11] Caldow G L, Deeley C M, Turner P H, Mills I M 1981 Chem. Phys. Lett. 82 434
[12] Cai Z L, Bai J L 1993 Chem. Phys. 178 215
[13] Hebner G A 2002 Appl. Surf. Sci. 192 161
[14] Zhao J, Cheng X L, Yang X D, Zhu Z H 2009 Acta Phys. Sin. 58 5280 (in Chinese) [赵俊, 程新路, 杨向东, 朱正和 2009 58 5280]
[15] Chase M W, Davies C A, Downey J R 1985 J. Phys. Chem. Ref. Data 14 (Suppl. 1) 553
[16] Zhu Z H, Yu H G 1997 Molecular Structure and Molecular Potential Energy Function (Beijing: Science Press) (in Chinese) [朱正和, 俞华根 1997 分子结构和势能函数 (北京: 科学出版社)]
[17] Jan H, Zdenek H, Suehiro I 1999 Int. J. Mass. Spectrom. 192 165
[18] Han X Q, Xiao X J, Liu Y F 2011 J. Atom. Mol. Phys. 28 195 (in Chinese) [韩晓琴, 肖夏杰, 刘玉芳 2011 原子与分子 28 195]
[19] Han X Q, Xiao X J, Liu Y F 2013 Acta Phys. Sin. 62 193101 (in Chinese) [韩晓琴, 肖夏杰, 刘玉芳 2013 62 193101]
[20] Zeng H, Zhao J 2014 Acta Phys. Sin. 63 063101 (in Chinese) [曾晖, 赵俊 2014 63 063101]
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