The debye (symbol: D) (/dɛˈbaɪ/;[1]Dutch:[dəˈbɛiə]) is a CGS unit[2] (a non-SImetric unit) of electric dipole moment[note 1] named in honour of the physicist Peter J. W. Debye. It is defined as 10−18statcoulomb-centimetres.[note 2] Historically the debye was defined as the dipole moment resulting from two charges of opposite sign but an equal magnitude of 10−10 statcoulomb[note 3] (generally called e.s.u. (electrostatic unit) in older scientific literature), which were separated by 1 ångström.[note 4] This gave a convenient unit for molecular dipole moments.
Typical dipole moments for simple diatomic molecules are in the range of 0 to 11 D. Symmetric homoatomic species, e.g. chlorine, Cl2, have zero dipole moment, and highly ionic molecular species have a very large dipole moment, e.g. gas-phase potassium bromide, KBr, with a dipole moment of 10.41 D.[3] A proton and an electron 1 Å apart have a dipole moment of 4.8 D.
The debye is still used in atomic physics and chemistry because SI units have until recently been inconveniently large. The smallest SI unit of electric dipole moment is the quectocoulomb-metre,[note 9] which corresponds closely to 0.3 D.
^Two equal and opposite charges separated by some distance constitute an electric dipole. This dipole possesses an electric dipole moment whose value is given as charge times length of separation. The dipole itself is a vector whose direction coincides with the position vector of the positive charge with respect to the negative charge:
p = qr.
^ abThe statcoulomb is also known as the franklin or electrostatic unit of charge.
1 statC = 1 Fr = 1 esu = 1 cm3/2⋅g1/2⋅s−1.
^10−10 statcoulomb corresponds to approximately 0.2083 units of elementary charge.
^The ångström is within an order of magnitude of the nuclear separation for a typical covalent bond.
1 Å = 100 pm = 10−8 cm = 10−10 m.
^In any of the CGS systems, electromagnetic units are expressed in terms of the three base units, cm, g and s, albeit the systems are mutually inconsistent in this regard.
^One debye corresponds to 10−21 C·m2/s divided by the speed of light. Conversely, 1 C·m ≘ 2.9979×1029 D.
^CGS units 2011-08-09 at the Wayback Machine R. Rowlett (University of North Carolina at Chapel Hill).
^Physical chemistry 2nd Edition (1966) G. M. Barrow. McGraw-Hill.
February 15, 2024
debye, other, uses, disambiguation, debye, symbol, dutch, dəˈbɛiə, unit, metric, unit, electric, dipole, moment, note, named, honour, physicist, peter, defined, statcoulomb, centimetres, note, historically, debye, defined, dipole, moment, resulting, from, char. For other uses see Debye disambiguation The debye symbol D d ɛ ˈ b aɪ 1 Dutch deˈbɛie is a CGS unit 2 a non SI metric unit of electric dipole moment note 1 named in honour of the physicist Peter J W Debye It is defined as 10 18 statcoulomb centimetres note 2 Historically the debye was defined as the dipole moment resulting from two charges of opposite sign but an equal magnitude of 10 10 statcoulomb note 3 generally called e s u electrostatic unit in older scientific literature which were separated by 1 angstrom note 4 This gave a convenient unit for molecular dipole moments 1 D 10 18 statC cm 10 18 cm5 2 g1 2 s 1 note 5 10 10 statC A note 2 1 299792 458 10 21 C m note 6 3 33564 10 30 C m note 7 0 3934303 e a0 note 8 0 2081943 e A 0 020819 43 e nmTypical dipole moments for simple diatomic molecules are in the range of 0 to 11 D Symmetric homoatomic species e g chlorine Cl2 have zero dipole moment and highly ionic molecular species have a very large dipole moment e g gas phase potassium bromide KBr with a dipole moment of 10 41 D 3 A proton and an electron 1 A apart have a dipole moment of 4 8 D The debye is still used in atomic physics and chemistry because SI units have until recently been inconveniently large The smallest SI unit of electric dipole moment is the quectocoulomb metre note 9 which corresponds closely to 0 3 D See also editBuckingham unit CGS unit of electric quadrupole Notes edit Two equal and opposite charges separated by some distance constitute an electric dipole This dipole possesses an electric dipole moment whose value is given as charge times length of separation The dipole itself is a vector whose direction coincides with the position vector of the positive charge with respect to the negative charge p qr a b The statcoulomb is also known as the franklin or electrostatic unit of charge 1 statC 1 Fr 1 esu 1 cm3 2 g1 2 s 1 10 10 statcoulomb corresponds to approximately 0 2083 units of elementary charge The angstrom is within an order of magnitude of the nuclear separation for a typical covalent bond 1 A 100 pm 10 8 cm 10 10 m In any of the CGS systems electromagnetic units are expressed in terms of the three base units cm g and s albeit the systems are mutually inconsistent in this regard One debye corresponds to 10 21 C m2 s divided by the speed of light Conversely 1 C m 2 9979 1029 D Also expressible as 3 33564 qC m The product e a0 is also called the atomic unit of electric dipole moment see Atomic unit of electric dipole moment NIST With a value of 10 30 quecto is the smallest SI prefix accepted as an SI prefix by the CGPM on 18 November 2022 References edit Debye Random House Dictionary 2013 CGS units Archived 2011 08 09 at the Wayback Machine R Rowlett University of North Carolina at Chapel Hill Physical chemistry 2nd Edition 1966 G M Barrow McGraw Hill Retrieved from https en wikipedia org w index php title Debye amp oldid 1184291581, wikipedia, wiki, book, books, library,
