Liu Fuyi, Zhang X G, Armentrout P B
Department of Chemistry, University of Utah, 315 S. 1400 E. Rm. 2020, Salt Lake City 84112 Utah, USA.
Phys Chem Chem Phys. 2005 Mar 7;7(5):1054-64. doi: 10.1039/b500639m.
The kinetic energy dependence of the reaction of Ni+ (2D) with methane has been studied using guided ion beam mass spectrometry. Formation of NiH+, NiCH2+ and NiCH3+ are all observed with thresholds near 2 eV, and NiCH+ is observed at higher kinetic energies. The dehydrogenation reaction is shown to proceed over a barrier in excess of the endothermicity by examining the reverse reaction of NiCH2(+) + D2. Collision-induced dissociation of NiCH2+ and NiCH4+ with Xe provides additional information on the products and reaction intermediates. Modeling of the endothermic reaction cross sections yields the 0 K bond dissociation energies (in eV) of D0(Ni( +)-H) = 1.60 +/- 0.08, D0(Ni(+)-CH) = 3.12 +/- 0.12, D0(Ni(+)-CH2) = 3.20 +/- 0.08, D0(Ni(+)-CH3) = 1.76 +/- 0.07, and D0(Ni(+)-CH4) = 1.00 +/- 0.05. The experimental thermochemistry is favorably compared with previous experimental results and density functional theory calculations (B3LYP), which also establish the electronic structures of these species and provide insight into the reaction mechanism. The results for Ni(+) are compared with those for the third-row transition metal congener Pt+ and the differences in behavior and mechanism are discussed.
利用导向离子束质谱法研究了Ni+(2D)与甲烷反应的动能依赖性。观察到NiH+、NiCH2+和NiCH3+的形成，其阈值均接近2 eV，在较高动能下观察到NiCH+。通过研究NiCH2(+) + D2的逆反应，表明脱氢反应是在超过吸热性的势垒上进行的。NiCH2+和NiCH4+与Xe的碰撞诱导解离提供了有关产物和反应中间体的更多信息。对吸热反应截面的建模得出了0 K时的键解离能（单位为eV）：D0(Ni( +)-H) = 1.60 +/- 0.08，D0(Ni(+)-CH) = 3.12 +/- 0.12，D0(Ni(+)-CH2) = 3.20 +/- 0.08，D0(Ni(+)-CH3) = 1.76 +/- 0.07，以及D0(Ni(+)-CH4) = 1.00 +/- 0.05。将实验热化学与先前的实验结果和密度泛函理论计算（B3LYP）进行了良好的比较，这些计算还确定了这些物种的电子结构，并深入了解了反应机理。将Ni(+)的结果与第三行过渡金属同族元素Pt+的结果进行了比较，并讨论了行为和机理上的差异。
