Positron Binding Properties of Glycine and Its Aqueous Complexes
Positron Binding Properties of Glycine and Its Aqueous Complexes
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DOI：
10.1021/acs.jpca.6b01780
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发表时间：
2016-06-16
影响因子：
2.9
通讯作者：
Tachikawal, Masanori
中科院分区：
文献类型：
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作者：
Numrnela, Mikko;Raebiger, Hannes;Tachikawal, Masanori
我们用第一性原理计算研究了正电子与甘氨酸及其水溶液配合物的结合。我们表明，虽然甘氨酸在基态（Gly）不结合正电子，但它的几个强极性构象可以，特别是它的两性离子形式（GlyZI）强烈结合正电子。水溶液配合物Gly中心点nH(2)O和GlyZI中心点nH(2)O也能结合正电子，如果它们的偶极矩为mu > mu（cr）。然而，mu不足以描述正电子与三种配合物的结合。我们发现，除了mu，正电子结合强烈依赖于甘氨酸的分子内键。在Gly中心点H2O中，正电子与Gly中的氮弱结合，而在GlyZI中心点nH(2)O中，GlyZI中的离子氧是强的“正电子吸引子”。
We investigate positron binding to glycine and its aqueous complexes by first-principles calculation. We show that while glycine in its ground state (Gly) does not bind positrons, several of its strongly polar conformers do, and in particular, its zwitterion form (GlyZI) binds positrons strongly. Aqueous complexes Gly center dot nH(2)O and GlyZI center dot nH(2)O also bind positrons, if their dipole moment mu > mu(cr). However, mu is not a sufficient quantity to describe positron binding to thee complexes. We show that in addition to mu, positron binding strongly depends on the intramolecular bonding of glycine. In Gly center dot H2O, positrons are weakly bound to the nitrogen in Gly, whereas in GlyZI center dot nH(2)O, the ionic oxygen in GlyZI is a strong "positron attractor".