Probability density, or electron density (ψ²), is the square of the wave function, and it gives the likelihood of finding the electron at a particular point in space. Unlike the wave function itself, which has no direct physical meaning, ψ² is a measurable, physically real quantity. Regions where ψ² is large are where the electron is most likely to be found.

概率密度(电子密度,ψ²)是波函数的平方,它给出在空间某一点找到电子的可能性。波函数本身无直接物理意义,而 ψ² 则是可测量的、具有物理实在性的量。ψ² 较大的区域即电子最可能出现的地方。