几个重要的基元反应的动力学研究
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摘要
分子反应动力学是在分子水平上研究化学反应微观动态和机理的一门学科。它不仅是宏观化学运动学的基础，同时也为解释基元化学反应中的基本现象提供了丰富的知识。长期以来人们致力于化学反应的精确量子动力学研究，并发展了许多研究方法。目前含时波包量子动力学方法已经成为人们研究三原子和四原子体系强有力的计算工具。采用的量子力学方法能够完全从量子力学基本原理出发，真实而完全的反映原子核在势能面上的运动。相对非含时方法，含时波包方法有许多优点，除了数值计算上效率高之外，它还为动力学提供了物理意义明确而直观的图像，具有经典的直观性又不乏量子力学的准确性，因而，受到人们的喜爱。含时波包方法已经用于研究了许多三原子和四原子反应体系了，但是对反应的含时波包精确计算至今仍是一项非常复杂的工作。
在气相化学反应动力学发展过程中，H+HCl及其同位素衍生物反应起着非常重要的作用；在大气化学和燃烧化学中，F+CH_4及其同位素衍生物的反应是氢提取和高放热反应的一个典型反应原型。所以本文对它们进行了研究。
本文采用含时量子波包方法(理论)对三原子反应H+HCl，H+DCl，D+HCl，D+DCl进行了精确的全维计算，在由Bian和Wemer提出的BW2势能面上研究了它们的动力学行为。当为线性过渡态时，该势能面上提取反应通道的经典势垒为0.184eV，对于交换反应通道也存在一个线性过渡态计算的势垒为0.776eV。计算了这四个反应在给定初始态下的反应几率，积分反应截面及初始态为激发态对反应过程及结果的影响等。在分析结果的时候我们将零点能和隧道效应同时考虑在内。再利用J-shifting方法计算了反应的速率常数。
为了实现量子动力学含时波包方法对多原子反应体系的研究，本文采用张增辉教授提出的一个半刚性振转子(SVRT)的模型，对F+CH_4反应及其同位素衍生物反应进行了含时波包动力学的研究。其势能面用了矫正后的儿势能面已由Corchado，J．C．报道。该势能面的反应势垒0.066eV。实验和理论研究表明在反应中C-H键不影响反应碰撞，它只是一个旁观者。在本文中C-H键作为常数处理使得计算大大简化了。我们计算得到了不同初始振转态的总反应几率，积分反应截面和速率常数。从得到的数值结果可以看出，总反应几率随着碰撞能有一个很尖锐的峰，这一般来讲是与动力学振荡有关系。
并将所有反应的结果和已有的理论以及实验结果进行了比较，发现它们符合得很好，我们又详细的分析了一些细微的差别及这些反应的立体动力学行为。
Molecule reaction dynamics is a science of studying microcopic feature and mechanism of chemical reaction in molecular and atomic level. It can provide basic knowledge for interpreting general phenomena in the chemical reactions, and become the base of the macroscopic reaction dynamics.
Quantum approach could describe the motion of atomic nuclear on the potential energy surface vividly and completely based on the first principle. Much effort has been devoted to the development of accurate quantum dynamics methods to perform reaction scattering calculation for elementary chemical reactions. At present, time-dependent (TD) quantum wave packet approach has emerged as a powerful computational tool for studying quantum reaction dynamics of triatomic and tetraatomic systems. The main attraction of solving the time-dependent, as opposed to the time-independent, Schrodinger equation stems from its favorable computational scaling with the number of basis functions. This makes the TD wavepacket approach an attractive choice for studying reaction dynamics of large molecular systems. In addition, the TD wavepacket approach is conceptually simple and provides a classical-like interpretation of the numerical results through time propagation of the wavepacket.
The gas-phase reaction of H+HC1 and the corresponding to isotopic reactions system have played a major role in the development of chemical kinetics and to the environment in atmospheric chemistry. The reaction of fluorine atom with methane F+CH4HF+CH3 reaction and the corresponding isotopic reactions have been played an important role in atmospheric and combustion chemistry which deserves us to have more study. The reaction systems represent an especially important prototype for highly exothermic hydrogen abstraction reactions of F with hydrocarbons.
A theoretical study of the dynamics is given in the thesis of the H+HC1, H+DC1, D+HC1, D+DC1 systems on the potential energy surface (PES) pubilshed by Bian and Werner. In the present work, the four reaction probabilities have been calculated by employing TDWP method for several values of the total angular momentum quantum number J> 0. Reaction probabilities are calculated from various initial rotational states of the reagent. The effects of the zero-point energy and the tunneling effect of the reactions are considered for depicting the behavior of the reactions. Those have then been used to estimate cross sections for exchanged and abstraction channels. The abstraction reaction for the H+HC1 reaction has a collinear transition state, and for the H+HC1 exchange reaction, which also has a collinear transition state. The thermal rate constants of HC1 are calculated by employing the uniform J -shifting method, and a comparison with experimental measurement is provided.
In this work, the reaction of fluorine with methane and the isotopic reactions system are calculated through the time-dependent quantum scattering, which has been carried out using the SVRT model, based on the analytic the modified Jl (MJ1) PES which reported by Corchado, J. C. etc. The barrier height about 1.8Kcal/mol, which among the experimental estimate of 0.96-2.39 kcal/mol. The reagent molecule CH4 that is consisted of an H atom and a CH3 fragment which is treated as a semirigid vibrating rotor. The fragment CH3 is fixed in the geometry in the basic SVRT model. For example, since during the reactant to the
transition state the C-H bond in the CH3 group essentially remains constant, which can be treated as a spectator bond, therefore we fixed it at its transition state value-1.090A.
In the current study, reaction probability, cross section, and rate constant are calculated for the title reaction from the ground state of the reagent on the MJl PES. Numerical calculation shows that the oscillatory structures in the energy dependence of the calculated reaction probability. Those structures are generally associated with broad dynamical resonances.
The calculated results can compared with the results of previous calculations in the references and reaction dynam
在气相化学反应动力学发展过程中，H+HCl及其同位素衍生物反应起着非常重要的作用；在大气化学和燃烧化学中，F+CH_4及其同位素衍生物的反应是氢提取和高放热反应的一个典型反应原型。所以本文对它们进行了研究。
本文采用含时量子波包方法(理论)对三原子反应H+HCl，H+DCl，D+HCl，D+DCl进行了精确的全维计算，在由Bian和Wemer提出的BW2势能面上研究了它们的动力学行为。当为线性过渡态时，该势能面上提取反应通道的经典势垒为0.184eV，对于交换反应通道也存在一个线性过渡态计算的势垒为0.776eV。计算了这四个反应在给定初始态下的反应几率，积分反应截面及初始态为激发态对反应过程及结果的影响等。在分析结果的时候我们将零点能和隧道效应同时考虑在内。再利用J-shifting方法计算了反应的速率常数。
为了实现量子动力学含时波包方法对多原子反应体系的研究，本文采用张增辉教授提出的一个半刚性振转子(SVRT)的模型，对F+CH_4反应及其同位素衍生物反应进行了含时波包动力学的研究。其势能面用了矫正后的儿势能面已由Corchado，J．C．报道。该势能面的反应势垒0.066eV。实验和理论研究表明在反应中C-H键不影响反应碰撞，它只是一个旁观者。在本文中C-H键作为常数处理使得计算大大简化了。我们计算得到了不同初始振转态的总反应几率，积分反应截面和速率常数。从得到的数值结果可以看出，总反应几率随着碰撞能有一个很尖锐的峰，这一般来讲是与动力学振荡有关系。
并将所有反应的结果和已有的理论以及实验结果进行了比较，发现它们符合得很好，我们又详细的分析了一些细微的差别及这些反应的立体动力学行为。
Molecule reaction dynamics is a science of studying microcopic feature and mechanism of chemical reaction in molecular and atomic level. It can provide basic knowledge for interpreting general phenomena in the chemical reactions, and become the base of the macroscopic reaction dynamics.
Quantum approach could describe the motion of atomic nuclear on the potential energy surface vividly and completely based on the first principle. Much effort has been devoted to the development of accurate quantum dynamics methods to perform reaction scattering calculation for elementary chemical reactions. At present, time-dependent (TD) quantum wave packet approach has emerged as a powerful computational tool for studying quantum reaction dynamics of triatomic and tetraatomic systems. The main attraction of solving the time-dependent, as opposed to the time-independent, Schrodinger equation stems from its favorable computational scaling with the number of basis functions. This makes the TD wavepacket approach an attractive choice for studying reaction dynamics of large molecular systems. In addition, the TD wavepacket approach is conceptually simple and provides a classical-like interpretation of the numerical results through time propagation of the wavepacket.
The gas-phase reaction of H+HC1 and the corresponding to isotopic reactions system have played a major role in the development of chemical kinetics and to the environment in atmospheric chemistry. The reaction of fluorine atom with methane F+CH4HF+CH3 reaction and the corresponding isotopic reactions have been played an important role in atmospheric and combustion chemistry which deserves us to have more study. The reaction systems represent an especially important prototype for highly exothermic hydrogen abstraction reactions of F with hydrocarbons.
A theoretical study of the dynamics is given in the thesis of the H+HC1, H+DC1, D+HC1, D+DC1 systems on the potential energy surface (PES) pubilshed by Bian and Werner. In the present work, the four reaction probabilities have been calculated by employing TDWP method for several values of the total angular momentum quantum number J> 0. Reaction probabilities are calculated from various initial rotational states of the reagent. The effects of the zero-point energy and the tunneling effect of the reactions are considered for depicting the behavior of the reactions. Those have then been used to estimate cross sections for exchanged and abstraction channels. The abstraction reaction for the H+HC1 reaction has a collinear transition state, and for the H+HC1 exchange reaction, which also has a collinear transition state. The thermal rate constants of HC1 are calculated by employing the uniform J -shifting method, and a comparison with experimental measurement is provided.
In this work, the reaction of fluorine with methane and the isotopic reactions system are calculated through the time-dependent quantum scattering, which has been carried out using the SVRT model, based on the analytic the modified Jl (MJ1) PES which reported by Corchado, J. C. etc. The barrier height about 1.8Kcal/mol, which among the experimental estimate of 0.96-2.39 kcal/mol. The reagent molecule CH4 that is consisted of an H atom and a CH3 fragment which is treated as a semirigid vibrating rotor. The fragment CH3 is fixed in the geometry in the basic SVRT model. For example, since during the reactant to the
transition state the C-H bond in the CH3 group essentially remains constant, which can be treated as a spectator bond, therefore we fixed it at its transition state value-1.090A.
In the current study, reaction probability, cross section, and rate constant are calculated for the title reaction from the ground state of the reagent on the MJl PES. Numerical calculation shows that the oscillatory structures in the energy dependence of the calculated reaction probability. Those structures are generally associated with broad dynamical resonances.
The calculated results can compared with the results of previous calculations in the references and reaction dynam
引文
1. G.. G.. Balint Kurti, Adv. Chem. Phys, 1975, 30:137
2. M.Karplus, R.Porter, R.D.Sharma, J. Chem. Phys, 1965, 49:3259
3. J.D.DolI, Chem. Phys, 1974, 3:257
4. D.G.. Truhlar, T. Muckermanin, In Physics of Atoms and Molecules, Ed. R. B. Berstein, Plenum, New York, 1979.
5. S.A.Adelman, J.D.DolI, J.Chem. Phys, 1974, 61:4242
6. S.A.Adelman, J.D.DolI, J.Chem. Phys, 1975, 63:4906
7. S.A.Adelman, J.D.Doll, J.Chem. Phys, 1975, 64:2375
8. S.A.Adelman, Adv. Phys. Chem, 1983, 53:61
9. J.C.Tully, Acc. Chem. Res, 1981, 14:188
10. T.J.Polfe, S.A.Rice, JoChem. Phys, 1983, 79:4863
11. W.H.Miller, J.Chem. Phys, 1971, 54:5386
12. W.H.Miller, Adv. Chem. Phys, 1974, 25:69
13. W.H.Miller, Adv. Chem. Phys, 1974, 30:77
14. J.D.DolI, Chem. Phys, 1974, 3:257
15. J.D.Doll, J.Chem. Phys, 1974, 61:954
16. R.I.Masel, R.P. Merril, W.H.Miller, J.Chem. Phys, 1976, 64:45
17. R.I.Masel, R.P. Merril, W.H.Miller, Surf. Sci, 1974, 46:681
18. E.J.Heller, J.Chem. Phys, 1975, 62:1544
19. E.J.Heller, J.Chem. Phys, 1976, 65:1289
20. E.J.Heller, J.Chem. Phys, 1976, 65:4979
21. E.J.Heller, J.Chem. Phys, 1977, 67:3339
22. E.J.Heller, J.Chem. Phys, 1978, 68:2066
23. E.J.Heller, J.Chem. Phys, 1978, 68:3891
24. E.J.Heller, J.Chem. Phys, 1981, 75:2923
25. E.J.Heller, Acc. Chem. Res, 1981, 14:386
26. K.Kulander, E.J.Heller, J.Chem. Phys, 1978, 69:2439
27. M.J.Davis, E.J.Heller, J.Chem. Phys, 1979, 71:3383
28. S.Y. Lee, E.J.Heller, J.Chem. Phys, 1979, 71:4777
29. R.C.Brown, E.J.Heller, J.Chem. Phys, 1981, 75:186
30. S.Y. Lee, E.J.Heller, J.Chem. Phys, 1982, 76:3035
31. D.Tannor, E.J.Heller, J.Chem. Phys, 1982, 77:202
32. E.J.Heller, R.L.Sundberg, D.Tannor, J.Chem. Phys, 1983, 78:1882
33. M.Blanco, E.J.Heller, J.Chem. Phys, 1983, 78:2504
34. G.. Drolshagen, E.J.Heller, J.Chem. Phys, 1983, 79:2072
35. G.. Drolshagen, E.J.Heller, Surf. Sci, 1984, 139:260
36. G..Drolshagen, E.J.Heller, Chem. Phys. Lett, 1984, 104:129
37. G.. Drolshagen, Comment At. Mol. Phys, 1985, 17:47
38. Y. Weissman, J.Chem. Phys, 1979, 71:3880
39. G..Drolshagen, R.Vollmer, Chem. Phys. Lett, 1985, 122:333
40. R.Heather, H.Metiu, Chem. Phys. Lett, 1985, 188:558
41. B.Jackson, H.Metiu, J,Chem. Phys, 1985, 82:5707
42. B.Jackson, H.Metiu, J.Chem. Phys, 1985, 83:1952
43. S.Sawada, R.Heather, B.Jacson, H.Metiu, J.Chem. Phys, 1985, 83:3009
44. S.Sawada, H.Metiu, J.Chem. Phys, 1986, 84:227
45. J.Daniel, E.Heller, J.Chem. Phys, 1987, 87:5302
46. E.Schrodinger, Ann. Phys, 1926, 79:489
47. P. Ehrenfest, Z.Phys, 1927, 45:455
48. (a) D.C.Clary, J.Chem. Phys, 1991, 95:7298; (b) D.C.Clary, J.Chem. Phys, 1992, 96:3656; (c) G.. Nyman, D.C.Clary, J.Chem. Phys, 1995, 99:7774
49. Q.Sun and J.M.Bowman, J.Chem. Phys, 1990, 92:5201
50. J.C. Light, Discuss.Faraday Soc, 1969, 44:14
51. W.A.Wagner, J.Chem. Phys, 1976, 65:4343
52. G.Wolken, J.Chem. Phys, 1973, 58:3047
53. H.Chow, E.D.Thompson, Surf. Sci, 1976, 59, 225
54. G.C.Schatz, A.Kuppermann, J.Chem. Phys, 1976, 65:4668
55. M.J.Redmon, R.E.Wyatt, Chem. Phys. Lett, 1979, 63:209
56. J.F. McNutt, R.E.Wyatt, M.J.Redmon, J.Chem. Phys, 1984, 81:1692
57. J.M.Huston, C.Schartz, J.Chem.Phys, 1983, 79:5179
58. C.Schartz, Phys.Rev. B, Condens Matter 1986, 34:2834
59. C.Yu, K.B.Whaley, C.S.Hogg, S.Sibener, Phys. Rev. Lett, 1983, 51:2210
60. E.A. McCullough, R.E.Wyatt, J.Chem. Phys, 1969, 51:1253
61. E.A. McCullough, R.E.Wyatt, J.Chem. Phys, 1971, 54:3592
62. A.Askar A.S.Cakmak, J. Chem. Phys, 1978, 68:2794
63. D.Kosloff, R. Kosloff, J. Comput. Phys, 1983, 52:35
64. D.Kosloff, R. Kosloff, J.Chem. Phys, 1983, 79:1823
65. M.D.Feit, J.A.Fleck, J. Comput. Phys, 1982, 47:412
66. H.Tal-Ezer, J. Chem.Phys, 1984, 81:3967
67．唐壁玉 博士毕业论文
68．赵新生 化学反应理论导论 北京大学出版社 2003
69．孙康编著 宏观反应动力学及其解析方法 冶金工业出版社 1998
70．周鲁，刘钟海 复杂反应动力学基础 成都科技大学出版社 1994
2. M.Karplus, R.Porter, R.D.Sharma, J. Chem. Phys, 1965, 49:3259
3. J.D.DolI, Chem. Phys, 1974, 3:257
4. D.G.. Truhlar, T. Muckermanin, In Physics of Atoms and Molecules, Ed. R. B. Berstein, Plenum, New York, 1979.
5. S.A.Adelman, J.D.DolI, J.Chem. Phys, 1974, 61:4242
6. S.A.Adelman, J.D.DolI, J.Chem. Phys, 1975, 63:4906
7. S.A.Adelman, J.D.Doll, J.Chem. Phys, 1975, 64:2375
8. S.A.Adelman, Adv. Phys. Chem, 1983, 53:61
9. J.C.Tully, Acc. Chem. Res, 1981, 14:188
10. T.J.Polfe, S.A.Rice, JoChem. Phys, 1983, 79:4863
11. W.H.Miller, J.Chem. Phys, 1971, 54:5386
12. W.H.Miller, Adv. Chem. Phys, 1974, 25:69
13. W.H.Miller, Adv. Chem. Phys, 1974, 30:77
14. J.D.DolI, Chem. Phys, 1974, 3:257
15. J.D.Doll, J.Chem. Phys, 1974, 61:954
16. R.I.Masel, R.P. Merril, W.H.Miller, J.Chem. Phys, 1976, 64:45
17. R.I.Masel, R.P. Merril, W.H.Miller, Surf. Sci, 1974, 46:681
18. E.J.Heller, J.Chem. Phys, 1975, 62:1544
19. E.J.Heller, J.Chem. Phys, 1976, 65:1289
20. E.J.Heller, J.Chem. Phys, 1976, 65:4979
21. E.J.Heller, J.Chem. Phys, 1977, 67:3339
22. E.J.Heller, J.Chem. Phys, 1978, 68:2066
23. E.J.Heller, J.Chem. Phys, 1978, 68:3891
24. E.J.Heller, J.Chem. Phys, 1981, 75:2923
25. E.J.Heller, Acc. Chem. Res, 1981, 14:386
26. K.Kulander, E.J.Heller, J.Chem. Phys, 1978, 69:2439
27. M.J.Davis, E.J.Heller, J.Chem. Phys, 1979, 71:3383
28. S.Y. Lee, E.J.Heller, J.Chem. Phys, 1979, 71:4777
29. R.C.Brown, E.J.Heller, J.Chem. Phys, 1981, 75:186
30. S.Y. Lee, E.J.Heller, J.Chem. Phys, 1982, 76:3035
31. D.Tannor, E.J.Heller, J.Chem. Phys, 1982, 77:202
32. E.J.Heller, R.L.Sundberg, D.Tannor, J.Chem. Phys, 1983, 78:1882
33. M.Blanco, E.J.Heller, J.Chem. Phys, 1983, 78:2504
34. G.. Drolshagen, E.J.Heller, J.Chem. Phys, 1983, 79:2072
35. G.. Drolshagen, E.J.Heller, Surf. Sci, 1984, 139:260
36. G..Drolshagen, E.J.Heller, Chem. Phys. Lett, 1984, 104:129
37. G.. Drolshagen, Comment At. Mol. Phys, 1985, 17:47
38. Y. Weissman, J.Chem. Phys, 1979, 71:3880
39. G..Drolshagen, R.Vollmer, Chem. Phys. Lett, 1985, 122:333
40. R.Heather, H.Metiu, Chem. Phys. Lett, 1985, 188:558
41. B.Jackson, H.Metiu, J,Chem. Phys, 1985, 82:5707
42. B.Jackson, H.Metiu, J.Chem. Phys, 1985, 83:1952
43. S.Sawada, R.Heather, B.Jacson, H.Metiu, J.Chem. Phys, 1985, 83:3009
44. S.Sawada, H.Metiu, J.Chem. Phys, 1986, 84:227
45. J.Daniel, E.Heller, J.Chem. Phys, 1987, 87:5302
46. E.Schrodinger, Ann. Phys, 1926, 79:489
47. P. Ehrenfest, Z.Phys, 1927, 45:455
48. (a) D.C.Clary, J.Chem. Phys, 1991, 95:7298; (b) D.C.Clary, J.Chem. Phys, 1992, 96:3656; (c) G.. Nyman, D.C.Clary, J.Chem. Phys, 1995, 99:7774
49. Q.Sun and J.M.Bowman, J.Chem. Phys, 1990, 92:5201
50. J.C. Light, Discuss.Faraday Soc, 1969, 44:14
51. W.A.Wagner, J.Chem. Phys, 1976, 65:4343
52. G.Wolken, J.Chem. Phys, 1973, 58:3047
53. H.Chow, E.D.Thompson, Surf. Sci, 1976, 59, 225
54. G.C.Schatz, A.Kuppermann, J.Chem. Phys, 1976, 65:4668
55. M.J.Redmon, R.E.Wyatt, Chem. Phys. Lett, 1979, 63:209
56. J.F. McNutt, R.E.Wyatt, M.J.Redmon, J.Chem. Phys, 1984, 81:1692
57. J.M.Huston, C.Schartz, J.Chem.Phys, 1983, 79:5179
58. C.Schartz, Phys.Rev. B, Condens Matter 1986, 34:2834
59. C.Yu, K.B.Whaley, C.S.Hogg, S.Sibener, Phys. Rev. Lett, 1983, 51:2210
60. E.A. McCullough, R.E.Wyatt, J.Chem. Phys, 1969, 51:1253
61. E.A. McCullough, R.E.Wyatt, J.Chem. Phys, 1971, 54:3592
62. A.Askar A.S.Cakmak, J. Chem. Phys, 1978, 68:2794
63. D.Kosloff, R. Kosloff, J. Comput. Phys, 1983, 52:35
64. D.Kosloff, R. Kosloff, J.Chem. Phys, 1983, 79:1823
65. M.D.Feit, J.A.Fleck, J. Comput. Phys, 1982, 47:412
66. H.Tal-Ezer, J. Chem.Phys, 1984, 81:3967
67．唐壁玉 博士毕业论文
68．赵新生 化学反应理论导论 北京大学出版社 2003
69．孙康编著 宏观反应动力学及其解析方法 冶金工业出版社 1998
70．周鲁，刘钟海 复杂反应动力学基础 成都科技大学出版社 1994