n It takes discrete values, multiples of some integer n, and the multiplication factor is the ratio of the Planck constant divided by 2 pi where n takes one, two, three and so on.

这些离散的值乘以整数，乘积因子,是普朗克常数除以2π,其中n可以取1，2，3，等等。

麻省理工公开课 - 固态化学导论课程节选