Spherical harmonics

Gives the angular basis functions on the surface of a sphere, with degree \ell and order m, normalized so they are orthonormal. They appear whenever a problem with spherical symmetry is solved, such as atomic orbitals, multipole expansions and quantum angular momentum.

Y_\ell^m(\theta, \varphi) = \sqrt{\frac{2\ell+1}{4\pi}\frac{(\ell-|m|)!}{(\ell+|m|)!}}\, P_\ell^{|m|}(\cos\theta)\, e^{im\varphi}

What the symbols mean

spherical harmonic of degree \ell and order m, a complex function of polar angle \theta and azimuthal angle \varphi
degree (non-negative integer, \ell \geq 0)
order (integer with |m| \leq \ell)
polar (colatitude) angle, 0 \leq \theta \leq \pi
azimuthal angle, longitude on the sphere
associated Legendre polynomial of degree \ell and order |m|
imaginary unit

About this formula

  • FieldMathematics
  • TopicSpecial functions
  • LevelUniversity
  • Also calledspherical harmonic, spherical harmonic function, angular part of hydrogen wavefunction, spherical harmonics normalization, Laplace spherical harmonics
  • SourceWikidata Q877100

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