What we need to do is get rid of the Coulomb tag that we have - that's how we measure our electron charges - charge, and so we use this epsilon nought quite often, this permativity constant of a vacuum to make that conversion.

怎么量度电子电荷,所以我们会经常用到,这个epsilon，nought记号,这是真空中的介电常数,我们还要指出,这个介电常数。

麻省理工公开课 - 化学原理课程节选

In addition to that, we have that epsilon nought value, remember that's the permittivity constant in a vacuum, and basically that is what we use as a conversion factor to get from units. We don't want namely coulombs to units, we want that will allow us to cancel out in this equation.

这是电子的电荷，此外，我们有epsilon零，记住这是真空的介电常数，这是我们用来转换单位的转换常数,我们不想用库伦单位，我们希望这个可以在方程中约去它。

麻省理工公开课 - 化学原理课程节选