关于在键中共享质子的量子性质
1M. E. Tuckerman and M. L. Klein, Center for Molecular Modeling and Department of Chemistry, University of Pennsylvania, Philadelphia, PA 19104-6323, USA. D. Marx and M. Parrinello, Max-Planck-Institut fur Festkorperforschung, Heisenbergstrasse 1, 70569 Stuttgart, Germany.
Science (New York, N.Y.)
|February 7, 1997
概括
量子效应显著影响了充电水复合体中的质子转移. 虽然H5O2+的行为是经典的,但H3O2-依赖于量子零点运动,即使在室温下,由于键强度的差异.
科学领域:
- 物理化学 物理化学
- 量子化学 是一个量子化学.
- 计算化学的计算化学
背景情况:
- 在键系统中,质子转移对许多化学和生物过程至关重要.
- 像H5O2+和H3O2这样的带电水复合体作为研究键动态的模型系统.
- 了解热和量子波动的相互作用是阐明反应机制的关键.
研究的目的:
- 调查热与量子波动在H5O2+和H3O2-. .中的质子转移中的相对重要性.
- 分析强和中等强度键中共享的质子的行为.
- 为了将质子转移动态与键特性相关联,例如氧-氧分离.
主要方法:
- 使用ab initio计算技术来建模电子和核动力学.
- 在充电水复合体内模拟质子转移通路.
- 分析量子零点运动和热效应的贡献.
主要成果:
- 强结合的H5O2+中的质子表现出主要的经典行为.
- 在H3O2复合体中,具有低屏障键,量子零点运动即使在环境温度下也是至关重要的.
- 氧-氧距离的微小差异被确定为不同键强度和质子转移特征的原因.
结论:
- 量子效应对于理解某些具有键的系统中的质子转移至关重要,特别是那些具有较弱键的系统.
- 质子行为的观察到的差异与键的强度直接相关,受O-O分离的影响.
- 这些发现提供了关于水性环境中的质子动态和相关化学反应的基本机制的见解.
相关概念视频
00:54Electron Behavior
Electrons are negatively charged subatomic particles that are attracted to an orbit around the positively-charged nucleus of an atom. They reside in locations that are associated with energy levels called shells and are further organized into sub-shells and orbitals within each shell.Electrons Orbit the NucleusElectrons are found in specific locations outside of the nucleus. The shell in which an electron resides indicates the general energy level of the electron: those closer to the nucleus...
00:26Hydrogen Bonds
Hydrogen BondsHydrogen bonds are weak attractions between atoms that have formed other chemical bonds. One of these atoms is electronegative, like oxygen, and has a partial negative charge. The other is a hydrogen atom that has bonded with another electronegative atom and has a partial positive charge.Hydrogen Bonds Control the World!Because hydrogen has very weak electronegativity when it binds with a strongly electronegative atom, such as oxygen or nitrogen, electrons in the bond are...
02:48Bond Polarity, Dipole Moment, and Percent Ionic Character
Bond Polarity
02:56Free Energy and Equilibrium
The free energy change for a process may be viewed as a measure of its driving force. A negative value for ΔG represents a driving force for the process in the forward direction, while a positive value represents a driving force for the process in the reverse direction. When ΔGrxn is zero, the forward and reverse driving forces are equal, and the process occurs in both directions at the same rate (the system is at equilibrium).
Recall that Q is the numerical value of the mass action expression...
Recall that Q is the numerical value of the mass action expression...
01:09Electron Behavior
Electrons are negatively charged subatomic particles attracted to and orbit around the positively-charged nucleus of an atom. They reside in spaces associated with energy levels called shells and are further organized into subshells and orbitals within each shell.
Electrons Orbit the Nucleus
Electrons are found in specific locations outside of the nucleus. The shell in which an electron resides indicates the general energy level of the electron: those closer to the nucleus have less energy,...
Electrons Orbit the Nucleus
Electrons are found in specific locations outside of the nucleus. The shell in which an electron resides indicates the general energy level of the electron: those closer to the nucleus have less energy,...
01:04Hydrogen 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...