The debye (symbol: D) is a non-SI and non-CGS unit of electrical dipole moment. It is defined as 1×10−18 statcoulomb centimeter (or 1×10−20 esu m, or 1×10−18 Fr cm). In SI units, 1 D equals approximately 3.33564×10−30 coulomb-meter (exactly 1×10−20 m times e, the quantum of electric charge). It is named after the physicist Peter J. W. 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" (the Bohr radius times the elementary charge), which is about 2.54 D for which the SI units are inconveniently large, particularly since the smallest prefix is ×10−24 (e.g., 2.54 D = 8.47×10−6 yCm). Note that SI disallows the application of prefixes to both members of a compound unit (e.g., 2.54 D = 8.47 fC·fm) or the compounding of prefixes (e.g., 2.54 D = 8.47 µyCm), so there is currently no satisfactory solution to this problem of notation.
References
- Atomic unit of electric dipole moment NIST
- CGS units R. Rowlett (University of North Carolina at Chapel Hill)
