* 1 electron volt (eV) is the amount of energy gained by an electron when it moves through an electric potential difference of one volt.

* 1 joule (J) is the standard unit of energy in the International System of Units (SI).

The conversion factor between electron volts and joules is:

1 eV =1.602 × 10⁻¹⁹ J

Therefore, to convert from joules to electron volts, divide the energy value in joules by 1.602 × 10⁻¹⁹.

Example:

Let's say you have an energy value of 1.5 × 10⁻¹⁸ J. To convert it to electron volts:

1.5 × 10⁻¹⁸ J / 1.602 × 10⁻¹⁹ J/eV =9.36 eV