The electron volt (eV) is a small unit of energy convenient for expressing quantities per atom, such as ionisation energies and electron affinities. It is the energy gained by an electron moving through a potential difference of one volt. Because it refers to a single atom or particle, it complements the per-mole units (kJ/mol) used for bulk samples.

电子伏特(eV)是便于表示单个原子层面的量(如电离能和电子亲和能)的小能量单位。它是一个电子通过一伏特电势差所获得的能量。由于它针对单个原子或粒子,因此与用于宏观样品的每摩尔单位(kJ/mol)相补充。