The debye (symbol: D) is a non-SI and non-CGS unit of electrical dipole moment. It is defined as 10^-18 statcoulomb centimeter. In SI units, 1 D equals 3.33564*10^-30 coulomb meter. It is named after the physicist Peter Debye.

The debye is still used in atomic physics and chemistry. The dipole moments of atoms and molecules are typically on the order of the "atomic unit of electric dipole moment" (Bohr radius times elementary charge), which is about 2.54 D for which the SI units are inconveniently large unless prefixes are added to both units (e.g., 2.54 D = 8.47 fC·fm).

Reference

• "atomic unit of electric dipole moment: [1] ". NIST
• " cgs units: [2] ". R. Rowlett (University of North Carolina at Chapel Hill)