buckingham (unit)

The buckingham (symbol: B) is a CGS unit of electric quadrupole, named in honour of the chemical physicist A. David Buckingham who was the first to measure a molecular quadrupole moment.{{refn|

{{cite journal

| last1 = Buckingham | first1 = A. D. | author-link = A. David Buckingham

| last2 = Disch | first2 = R. L.

| doi = 10.1098/rspa.1963.0088

| title = The Quadrupole Moment of the Carbon Dioxide Molecule

| journal = Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences

| volume = 273 | issue = 1353

| page = 275

| year = 1963

| bibcode = 1963RSPSA.273..275B

}}}} It is defined as {{val|e=-26|u=statcoulomb-square centimetre}}. This is equivalent to 1 debye-ångström, where 1 debye = {{val|e=-18|u=statcoulomb-centimetre}} is the CGS unit of molecular dipole moment and 1 ångström = {{val|e=-8|u=cm}}.

One buckingham corresponds to the quadrupole moment resulting from two opposing dipole moments of equal magnitude of 1 debye that are separated by a distance of 1 ångström, a typical bond length. This is analogous to the debye for the dipole moment of two opposing charges of {{val|e=-10|u=statcoulomb}} separated by 1 ångström, and the name Buckingham for the unit was suggested by Peter Debye in 1963 in honour of Buckingham.{{refn|

{{citation

|journal=Chemical and Engineering News

|title=Birefringence Gives CO's

|year=1963

|volume=41 |issue=16

|pages=40–43

|doi=10.1021/cen-v041n016.p040

|url=https://pubs.acs.org/doi/epdf/10.1021/cen-v041n016.p040

}}}}{{refn|

{{citation

|editor1=D.C. Clary | editor2=B.J. Orr

|title=Optical, electric and magnetic properties of molecules. A review of the work of A.D. Buckingham

|publisher=Elsevier

|year=1997

|page=8

}}}}