C4H5N-(H2O)n氢键团簇的多光子电离与从头计算研究

在３５５、５３２ｎｍ激光波长下用ＴＯＦ质谱研究了Ｃ４Ｈ５Ｎ－（Ｈ２Ｏ）ｎ氢键团簇体系的多光子电离。二波长下均得到一系列Ｃ４Ｈ５Ｎ－（Ｈ２Ｏ）ｎ＾＋及质子化产物Ｃ４Ｈ５Ｎ－（Ｈ２Ｏ）ｎＨ＾＋。３５５ｎｍ下可能存在双光子共振电离过程,使得该波长下吡咯母体及团簇离子信号较５３２ｎｍ有明显增强。     

应用反射式飞行时间质谱仪研究氨团簇离子解离动力学

用直射式和反射式飞行时间质谱研究了氨分子团簇体系在３５５ｎｍ激光下的多光子电离,得到一系列的质子化团簇离子（ＮＨ３）ｎＨ＾＋,同时还观察到超价氨团簇离子（ＮＨ３）ｎＨ＾＋２。在反射式飞行时间质谱研究中观测到质子化氨团簇离子在自由飞行过程中的解离现象,表明在该实验条件下生成的质子化氨团簇离子是一些亚稳态团簇离子。对子离子产率的分析,得到质子化团簇离子解离速率常数,从而可以估计亚稳态团簇离子的寿命。团     

C4H5N-(H2O)n氢键团簇的多光子电离与从头计算研究

在355、532nm激光波长下用TOF质谱研究了C4H5N-(H2O)n氢键团簇体系的多光子电离。二波长下均得到一系列C4H5N-(H2O)n+及质子化产物C4H5N-(H2O)nH+。355nm下可能存在双光子共振电离过程,使得该波长下吡咯母体及团簇离子信号较532nm有明显增强。从头计算结果表明质子化产物的质子更可能连接于吡咯环的α-C原子,而不是N原子上,即光电离过程诱发了一个簇内的质子转移反应。在532nm下质子化产物的生成主要来自于一个发生于团簇内部的Penning电离或电荷转移过程。团簇的形成对吡咯光解产物的稳定化作用使得团簇系列C4H4N-(H2O)n+出现反常强度变化。     

High Resolution Crossed Beams Scattering Study of the F+HD→DF+H Reaction

采用高分辨的氢原子里德堡态标识的飞行时间谱技术,对F+HD→DF+H反应进行了交叉分子束研究. 在2.51～5.60 kJ/mol的8个碰撞能下,测得了部分转动态分辨的微分截面. 实验结果显示,反应产物角分布表现出显著的后向散射,随着碰撞能的提高,角分布会逐渐变宽. 确定了产物振动态分支比随碰撞能变化的关系. 结果显示产物DF表现出高度振动态反转布居,其中DF(v′=3)态是布居数最高的产物态,在3.97 kJ/mol以上还探测到产物DF(v′=1)的信号.     

NH2(A2A1,090,423)的电子猝灭和转动态-态传能

在束 气和束 束实验条件下,详细研究了NH2(A1,090,423)自由基分别与Ar,N2,O2和NH3碰撞引起的电子态猝灭和转动态 态传能,获得了总的猝灭截面σQ (分别为≤0.17、0.26、0.30和0.48 nm2),以及相对转动态 态传能截面.利用碰撞络合物模型计算的电子猝灭截面与实验测得的截面具有基本相同的趋势,表明长程吸引势在猝灭过程中起着重要的作用.同时还发现,转动态 态传能中相对截面随着碰撞对的折合质量的减小而下降.由于NH3具有较大的偶极矩以及O2的开壳层电子结构使得猝灭截面增大,而转动态 态传能截面减小.     

转动传能中NH2(~A)精细结构态变化的研究

利用高分辨光谱技术观察了NH2(~2A A,090)423(F1/F2)在单次碰撞条件下的精细态色散荧光光谱,发现NH2(~2A A1)在与闭壳层分子碰撞传能过程中,母能级的自旋-转动耦合守恒,从实验上直接证实了在开壳层-闭壳层分子碰撞过程中电子自旋为一旁观者的假设;由于长程作用力造成子能级具有保持原来自旋-转动耦合的倾向.     

F+H2→HF+H反应的全量子态分辨的散射动力学研究

A crossed molecular beams, state-to-state scattering study was carried out on the F+H2→HF+H reaction at the collision energy of 5.02 kJ/mol, using the highly sensitive H atom Rydberg tagging time-of-flight method. All the peaks in the TOF spectra can be clearly assigned to the ro-vibrational structures of the HF product. The forward scattering of the HF product at v′=3 has been observed. The small forward scattering of the HF product at v′=2 has also been detected. Detailed theoretical analysis is required in order to fully understand the dynamical origin of these forward scattering products at this high collision energy.     

氟原子与反式1,3-丁二烯分子反应动力学的理论研究

Theoretical studies of F atom reaction with trans-1,3-butadiene were carried out at the CCSD(T)/6-311G(d,p)/B3LYP/6-311G(d,p) levels. Energies and structures for all reactants, products and transition states were determined. Two reaction pathways involving the formation of the complexes CH2CHCHFCH2 and CH2CHCHCH2F were found in this reaction. Theoretical results suggest that the H atom channel observed in previous crossed beam experiment occurs likely via these two long-lived complex formation pathways. For the complex CH2CHCHFCH2 pathway, another reaction channel (C2H3+C2H3F) is also accessible. Relative importance of the C2H3+C2H3F channel versus the H formation channel via the same reaction pathway has also been estimated, suggesting that it would be difficult to observe the C2H3+C2H3F channel in a crossed molecular beam experiment. Theoretical analysis also shows that the HF formation proceeds via direct abstraction mechanisms, though it is likely a minor process in this reaction.