【作者】 李严；

【导师】 黄旭日；

【作者基本信息】 吉林大学 ， 物理化学， 2010， 博士

【摘要】 本文采用量子化学计算方法对几类重要的离子-分子反应以及自由基-分子反应进行详尽的理论研究。给出了反应物、中间体、过渡态以及产物的结构和能量。通过构造完整的势能面,讨论了可能的反应通道和反应机理。本文结果可以为星际空间中重要的离子/自由基-分子反应模型的建立提供理论依据并为未来的实验室合成星际空间的离子或分子提供可靠的信息。主要贡献如下:(1)在B3LYP和CCSD(T)理论水平下对HCN+与CH4、C2H2、C2H4和NH3反应的二重态势能面进行了详细的理论研究,讨论了可能的反应产物和反应机理。理论计算结果与实验结果基本一致,并对实验上未预测的反应通道和产物进行补充。有利于进一步理解泰坦星大气的组成和结构。(2)在B3LYP和G3B3理论水平下对基态碳原子C(3P)与C3H6和trans-C4H8的反应进行了研究。给出了详细的反应势能面信息。计算结果表明,该反应在星际空间发挥重要作用。(3)在B3LYP和G3B3理论水平下对CH自由基与C3H6和CH3CCH的反应势能面进行研究。给出了详尽的异构化和分解途径。预测了可能的反应产物和反应机理。对CH+C3H6反应,理论计算结果论证了实验上预测的反应通道,并确定了各产物的分支比;对CH+CH3CCH反应,理论计算结果与Goulay等人实验结果相一致,但却与Daugey等人以及Loison等人的实验结果存在很大差异。更多还原

【Abstract】 Reactions of ions and radicals play an important role in various fields, such as combustion processes, interstellar medium and planetary atmospheres. In this thesis, the potential energy surfaces of the ion/radical-molecule reactions of relevance to combustion chemistry, interstellar chemistry and planetary atmosphere chemistry have been expolored using quantum chemical methods. Important information such as geometries and energies of the reactant, isomers, transition states and products are obtained. Possible reaction channels as well as reaction mechanism are also provided. The results obtained in this thesis are compared with previous experimental findings and may shed some light on future experimental investigations of these kinds of reactions. The main results are summaried as follows:1. The potential energy surfaces for HCN⁺ reactions with CH₄, C₂H₂, C₂H4 and NH3are explored. The results are as follows:（1） Theoretical investigations on the doublet potential energy surface for the reaction of HCN+ with CH₄ are carried out, the main reaction channels are listed as:Path 1: RHCN⁺+CH₄→HCNH…CH₃⁺l→P₁（HCNH⁺+CH₃）Path 2: R HCN⁺+CH₄→HCNH…CH₃⁺ 1→HNCHCH₃⁺ 2→P₂（CH₃CNH⁺+H）Path 3: R HCN⁺+CH₄→HCNH…CH₃⁺ l→HCNHCH₃⁺3→H₂CNCH₃⁺4→CH₃NC（…H）H⁺ 6→P₃（HCNCH₃⁺+H）→P₄（CH₃⁺+HCN+H）Path 4: R HCN⁺+CH₄→NC（H）…HCH₃⁺ 8→NC（H）CH₄+ 9→P₅ （cNCHCH₂⁺+H₂）Path 5: R HCN⁺+CH₄→HCNH…CH₃⁺ 1→HNCHCH₃⁺ 2→HNCHCH₃⁺ 7→P₆（NCCH₃⁺+H₂）→P₇（HCCNH⁺+H₂+H）P₁（HCNH⁺+CH₃） is the most feasible product. P₂（CH₃CNH⁺+H） and P₃ （HCNCH₃⁺+H） are the second and third competitive products. Moreover, P₃ （HCNCH₃⁺+H） and P₆（NCCH₃⁺+H₂） can undergo further evolutions leading to P₄ （CH₃⁺+HCN+H） and P7（HCCNH⁺+H₂+H）, respectively. However, both of them are theomodynamically unfeasible. （2）Theoretical calculations on the potential energy of the HCN⁺+C₂H₂ reaction areperformed, main reaction pathways are as follows:Path 1: RHCN⁺+C₂H₂→-HCCHCHN⁺ 1→NCCHCH₂⁺ 4→Pi（H₂C₃N⁺+H）Path 2: R HCN⁺+C₂H₂→p-HCCHCHN⁺ 1→NCCHCH₂⁺ 4→P₂ （CN+C₂H₃⁺）Path 3: R HCN⁺+C₂H₂→p-HCCHCHN⁺ 1→NCCHCH₂⁺ 4→NCCCH₃+ 6→P₃（HC₃N⁺+H₂）Path 4: R HCN⁺+C₂H₂→HCNCHCH⁺ 3b→HCNCCH₂⁺ 14→P₇（C₂H₂++HCN）P1（H₂C3N⁺+H） is the most favorable product, P₇（C₂H₂⁺+HCN） and P₃（HC₃N⁺+H₂） may be the second and third feasible products, followed by the least possible product P₂（CN+C₂H₃⁺）.（3）For HCN⁺+C₂H₄ reaction, main reaction pathways are shown as:Path 1: RHCN⁺+C₂H₄→HCNCH₂CH₂⁺ 1→P₁（HCN+C₂H₄⁺）Path 2: R HCN⁺+C₂H₄→HCNCH₂CH₂⁺ 1→P₂（HCNCHCH₂⁺+H）Path 3: R HCN⁺+C₂H₄→HCNCH₂CH₂⁺ 1→NCCH₂CH₃+ 5→P₃（NCCH₂+CH₃⁺）Path 4: R HCN⁺+C₂H₄→N-cCHCH₂CH₂⁺ 3→c-CHCH₂CH₂N+ 4→CNCH₂CH₃⁺ 12→P₄（CN+C₂H₅⁺）Path 5: R HCN⁺+C₂H₄→HCNCH₂CH₂⁺ 1→NCCH₂CH₃⁺ 5→P₅（NCCHCH₂⁺+H₂）Path 6: R HCN⁺+C₂H₄→N-cCHCH₂CH₂⁺ 3→c-CHCH₂CH₂N⁺ 4→c-NHCH₂CH₂C+ 8→HNCCH₂CH₂⁺ 9→P₆（HNCCHCH₂⁺+H）P₁（HCN+C₂H₄⁺） and P₂（HCNCHCH₂⁺+H） are the major and minor product, respectively. Other products which may compete each other, are much less competitive.（4）For HCN⁺+NH₃ reaction, main pathways are as follows:Path 1: RHCN⁺+NH₃→HCNNH₃+ 1→HCN…NH₃⁺ 3→P₁（NH₃⁺+HCN）Path 2: R HCN⁺+NH₃→NCHNH₃+ 2→HNCHNH₂⁺ 12→HNC…HNH₂+ 13→P₃（NH₃⁺+HNC）Path 3: R HCN⁺+NH₃→NCHNH₃+ 2→HNCHNH₂⁺ 12→HNC…HNH₂+ 13→P₉（HCNH⁺+NH₂）Path 4: R HCN⁺+NH₃→NCHNH₃+ 2→HNCHNH₂⁺ 12→P₁₂（HNCNH_<sup>2++NH₂）Path 1 is the most competitive pathway. Path 2 and path 3 may compete each other.Path 4 may be the least possible pathway.3. A detailed theoretical study for the reactions of C（3P） with C₃H₆ and trans-C₄H₈ was investigated at G3B3//B3LYP/6-311G（d,p） level, the main results are as follows:（1） For C（³P）+C₃H₆ reaction, possible reaction pathways are as follows:Path 1: R C（³P）+C₃H₆→CH₃-cCHCCH₂ l→fra/w-CH₃CHCCH₂ 2a→CH₃C（…H）CCH₂ 3→P4（CH₃CCCH₂+H）Path 2: R C（³P）+C₃H₆→CH₃-cCHCCH₂ 1→CH₃CHCCH₂（2a,2b）→P5（CH₃CHCCH+H）Path 3: R C（³P）+C₃H₆→CH₃-cCHCCH₂ l→trans-CH₃CHCCH₂ 2aPath 4: R C（³P）+C₃H₆→CH₃-cCHCCH₂ 1→trans-CH₃CHCCH₂ 2a→cis-CH₃CHCCH₂2b→P7（CH₂CCH+CH₃）Path 1, 2 and 4 are the main pathways, they may compete each other. Path 3 is the minor pathway.（2）For C（3P）+ trans-C4H8 reaction, two feasible reaction pathways are obtained:Path 1: R C（3P）+ trans-C4H8→CH₃-cCHCCH-CH₃ l→cis-trans-CH₃CHCCHCH₃ 3a→CH₃CHCC（CH₃）…H6→P6（CH₃CHCCCH₃+H）Path 2: R C（³P）+trans-C4H8→CH₃-cCHCCH-CH₃ 1→cis-trans-CH₃CHCCHCH₃ 3a→P7（CH₃CHCCH+CH₃）Path 1 and path 2 may compete each other, both of which are the main channels. 3. A detailed mechanistic study was reported for the reactions of CH with C3H6 and CH₃CCH, the results are as follows:（1）For CH+C₃H₆ reaction, main reaction pathways are listed as:Path 1: R CH+C₃H₆→CH₃-cCHCHCH₂1 （a, b）→P₁（CH₃-cCHCHCH+H）Path 2: R CH+C₃H₆→CH₃-cCHCHCH₂1 （a, b）→P₂（CH₃-cCCHCH₂+H）Path 3: R CH+C₃H₆→CH₃-cCHCHCH₂1 （a, b）→P₃（cCHCHCH₂+CH₃）Path 4: R CH+C₃H₆→CH-CH₃CHCH₂ 2→CH₂CH₂CHCH₂ 4（a,b）→P4（cis-CH₂CHCHCH₂+H）Path 5: R CH+C₃H₆→CH…CH₃CHCH₂ 2→CH₂CH₂CHCH₂ 4 （a, b）→P₅（trans-CH₂CHCHCH₂+H）Path 4 and 5 may compete each other, they are the most possible pathways. Paths 1, 2 and 3 may have comparable contributions to the title reaction.（2）For CH+CH₃CCH reaction, main reaction pathways are as follows:Path 1: R CH+CH₃CCH→CH₃CCHCH 1a→CH₃-cCCHCH 2→P3（CH₃-cCCCH+H） Path 2: R CH+CH₃CCH→CH₃CCHCH 1a→CH₃CHCCH 3→P₅（CH₂CHCCH+H）Path 3: R CH+CH₃CCH→CH₃CCHCH la→CH₃CCCH₂ 4→P₆（CH₂CCCH₂+H）Path 4: R CH+CH₃CCH→CH₃CCHCH 1a→CH₂CHCHCH 5 （a, b, c, d）→P7（C₂H₂+C₂H₃）Path 1, 2 and 3 are the major reaction channels, they may compete each other. Path 4 is the minor reaction channel.更多还原