Direct dynamics study of N-protonated diglycine surface-induced dissociation. Influence of collision energy
Direct dynamics study of N-protonated diglycine surface-induced dissociation. Influence of collision energy
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N-质子化二甘氨酸表面诱导解离的直接动力学研究。
DOI：
10.1016/j.jasms.2003.08.014
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发表时间：
2003
影响因子：
3.2
通讯作者：
K. Song
中科院分区：
文献类型：
--
作者：
Yanfei Wang;W. Hase;K. Song
采用量子力学和分子力学（QM + MM）直接动力学经典轨道模拟方法研究了N-质子化双甘氨酸（gly）2 H+表面诱导解离（SID）中的能量传递和碎裂过程.肽离子与氢化金刚石{111}表面碰撞。Austin Model 1（AM 1）半经验电子结构理论用于（gly）2 H+分子内势，分子力学函数用于金刚石表面势和肽/表面分子间势。在30、50、70和100 eV的碰撞能量Ei和0°（垂直于表面）的碰撞角下进行模拟。能量转移到肽离子的百分比几乎与Ei无关，而能量转移到表面随着Ei的增加而增加。随着Eis增加，较小百分比的能量保留在肽翻译中。能量转移的这些趋势与以前的SID轨迹模拟是一致的。在每个Ei处，最可能导致断裂的初始途径是+H3 NCH 2-CONHCH 2COOH键的断裂。碎片化有两种一般机制。一种是传统的Rice-Ramsperger-Kassel-Marcus（RRKM）模型，其中肽离子通过与表面碰撞而被激活，“反弹”，然后在经历分子内振动能量再分配（IVR）后解离。另一种机制是离子在与表面碰撞时碎裂。破碎是产品渠道数量随着Ei增加而大幅增加的根源，即，在30 eV下为6，但在100 eV下为59。在高Ei下，破碎成为主要的解离机制。
A quantum mechanical and molecular mechanical (QM + MM) direct dynamics classical trajectory simulation is used to study energy transfer and fragmentation in the surface-induced dissociation (SID) of N-protonated diglycine, (gly)2H+. The peptide ion collides with the hydrogenated diamond {111} surface. The Austin Model 1 (AM1) semiempirical electronic structure theory is used for the (gly)2H+intramolecular potential and molecular mechanical functions are used for the diamond surface potential and peptide/surface intermolecular potential. The simulations are performed at collision energies Eiof 30, 50, 70, and 100 eV and collision angle of 0° (perpendicular to the surface). The percent energy transfer to the peptide ion is nearly independent of Ei, while energy transfer to the surface increases with increase in Ei. A smaller percent of the energy remains in peptide translation as Eiis increased. These trends in energy transfer are consistent with previous trajectory simulations of SID. At each Eithe most likely initial pathway leading to fragmentation is rupture of the+H3NCH2CONHCH2COOH bond. Fragmentation occurs by two general mechanisms. One is the traditional Rice-Ramsperger-Kassel-Marcus (RRKM) model in which the peptide ion is activated by its collision with the surface, “bounces off”, and then dissociates after undergoing intramolecular vibrational energy redistribution (IVR). The other mechanism is shattering in which the ion fragments as it collides with the surface. Shattering is the origin of the large increase in number of product channels with increase in Ei, i.e., 6 at 30 eV, but 59 at 100 eV. Shattering becomes the dominant dissociation mechanism at high Ei.