(H2O) n-集群的电子结合图案
Thomas Sommerfeld1, Kenneth D Jordan
1University of Pittsburgh, Department of Chemistry and Center for Molecular and Materials Simulations, Chevron Science Center, 219 Parkman Ave., Pittsburgh, Pennsylvania 15260, USA.
Journal of the American Chemical Society
|April 28, 2006
概括
研究人员探索了多余的电子如何与水结合. 发现了一种新的网络透状态,挑战了静电相互作用总是主导这些系统中的电子结合的想法.
科学领域:
- 物理化学 物理化学
- 计算化学的计算化学
- 量子力学就是量子力学.
背景情况:
- 在小水群中 (n<=7) 过多的电子结合被理解为表面状态.
- 在较大的水集群 (n>7) 中的结合机制受到辩论,与OH结合的静电相互作用是普遍的理论.
- 现有的模型不能完全解释在较大的中观察到的多样化的结合动机.
研究的目的:
- 为了研究中型水 (H2O) 中多余电子的结合动机n-为n=12-24.4.
- 阐明静电,偏振和相关效应在电子结合中的作用.
- 为了识别超越表面和腔体状态的新型结合状态.
主要方法:
- 使用量子德鲁德模型进行理论模拟.
- 研究的水集群 (H2O) n- 在n=12到24的尺寸范围内.
- 分析了具有变异双极时刻的同质体,以了解相互作用主导.
主要成果:
- 确定了一个新的结合动机:网络透状态,电子集成到结合网络中.
- 静电相互作用仅在具有较大的双极时刻的同位素中占主导地位.
- 对于缺少大双极时刻的异构体,极化和相关性效应成为主要的结合驱动因素.
- 网络透状态表明电子结合,即使没有显著的静电相互作用.
结论:
- 过多的电子与水集群的结合比以前假设的要复杂得多,有多种因素.
- 一个新的网络透结合状态存在,扩大了我们对水中的电子溶解的理解.
- 静电效应与极化/关联效应的相对重要性取决于星团的异构结构和二极极矩.
相关概念视频
Covalent Bonding and Lewis Structures
Compared to ionic bonds, which results from the transfer of electrons between metallic and nonmetallic atoms, covalent bonds result from the mutual attraction of atoms for a “shared” pair of electrons.
Lewis Structures of Molecular Compounds and Polyatomic Ions
To draw Lewis structures for complicated molecules and molecular ions, it is helpful to follow a step-by-step procedure as outlined:
Hybridization of Atomic Orbitals I
The mathematical expression known as the wave function, ψ, contains information about each orbital and the wavelike properties of electrons in an isolated atom. When atoms are bound together in a molecule, the wave functions combine to produce new mathematical descriptions that have different shapes. This process of combining the wave functions for atomic orbitals is called hybridization and is mathematically accomplished by the linear combination of atomic orbitals. The new orbitals that...
Molecular Orbital Theory II
Molecular Orbital Energy Diagrams
VSEPR Theory
Valence shell electron-pair repulsion theory (VSEPR theory) enables us to predict the molecular structure around a central atom from an examination of the number of bonds and lone electron pairs in its Lewis structure. The VSEPR model assumes that electron pairs in the valence shell of a central atom will adopt an arrangement that minimizes repulsions between these electron pairs by maximizing the distance between them. The electrons in the valence shell of a central atom form either bonding...
Hydrogen Bonds
A hydrogen bond is formed when a weakly positive hydrogen atom already bonded to one electronegative atom (for example, the oxygen in the water molecule) is attracted to another electronegative atom from another polar molecule, such as water (H2O), hydrogen fluoride (HF), or ammonia (NH3). The huge electronegativity difference between the H atom (2.1) and the atom to which it is bonded (4.0 for an F atom, 3.5 for an O atom, or 3.0 for an N atom), combined with the very small size of an H atom...


