Surface-induced reactions and dissociations of small acetone, acetonitrile and ethanol cluster ions: competitive chemical reactions, dissociation mechanisms and determination of dissociation energy
Surface-induced reactions and dissociations of small acetone, acetonitrile and ethanol cluster ions: competitive chemical reactions, dissociation mechanisms and determination of dissociation energy
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小丙酮、乙腈和乙醇簇离子的表面诱导反应和解离：竞争性化学反应、解离机制和解离能的测定
DOI：
10.1088/1367-2630/5/1/309
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发表时间：
2003
期刊：
影响因子：
--
通讯作者：
T. Märk
中科院分区：
文献类型：
--
作者：
C. Mair;J. Fedor;M. Lezius;P. Scheier;M. Probst;Z. Herman;T. Märk
使用最近委托的串联质谱系统BESTOF，我们对各种分子簇离子（包括化学计量丙酮和乙腈簇离子和质子化乙醇簇离子）与碳氢化合物覆盖的不锈钢表面的相互作用进行了系统的研究（也使用氘化分子）。除了观察到表面碰撞中由能量转移驱动的化学计量簇离子的竞争性化学反应（簇内反应与表面h原子拾取反应）外，我们还能够清楚地看到单分子解离动力学决定了碰撞能量分辨质谱（CERMS）中观察到的衰变模式的产生。从这些CERMS的特征位移可以推导出相应的结合能，即{D}((CD3CN)2+ - CD3CN) = 0.66 eV, {D}((C2H5OH)2H+ - C2H5OH) = 0.95 eV，对于质子化二聚体{D}((C2H5OH)H+ - C2H5OH) = 1.6 eV。第一个值与目前使用B3LYP （Becke-Lee-Yang-Parr）密度泛函和6-311G（d, p）基集计算的值吻合良好，后一个值与早期从热化学数据中得出的值吻合良好。此外，在质子化乙醇簇离子的情况下，有可能得到由单体、二聚体和三聚体CERMS数据组成的三聚体的单一（通用）击穿图。这可以通过重新规范化CERMS中单体、二聚体和三聚体离子的能量尺度来实现（考虑到从平动到内能的转换，并假设簇的行为像具有相应自由度的统计系综）。
Using a recently commissioned tandem mass spectrometer system, BESTOF, we have carried out systematic investigations (using also deuterated molecules) on the interaction of various molecular cluster ions (including stoichiometric acetone and acetonitrile cluster ions and protonated ethanol cluster ions) with a hydrocarbon-covered stainless steel surface. Besides observing competitive chemical reactions for the stoichiometric cluster ions driven by the energy transfer in the surface collision (intra-cluster reactions versus surface H-atom pick-up reactions), we were able to see clear evidence that unimolecular dissociation kinetics determines the production of the observed decay patterns in collision energy-resolved mass spectra (CERMS). From characteristic shifts in these CERMS we can deduce corresponding binding energies, i.e., {D}((CD3CN)2+ - CD3CN) = 0.66 eV, {D}((C2H5OH)2H+ - C2H5OH) = 0.95 eV, and for the protonated dimer {D}((C2H5OH)H+ - C2H5OH) = 1.6 eV. The first value is in good agreement with values currently calculated using the B3LYP (Becke-Lee-Yang-Parr) density functional and the 6-311G(d, p) basis set, the latter values are in good agreement with values derived earlier from thermochemical data. Moreover, in the case of the protonated ethanol cluster ion, it is possible to arrive at a single (universal) breakdown graph for the trimer composed of data derived from monomer, dimer and trimer CERMS. This can be achieved by renormalizing the energy scale in the CERMS for the monomer, dimer and trimer ions (taking into account the conversion from translational to internal energy and assuming that the clusters behave like a statistical ensemble with the corresponding degrees of freedom).