库伦函数(Couloumb function)是下列常微分方程的解
d 2 w ( ρ ) d ρ 2 + ( 1 − 2 η ρ − l ∗ ( l + 1 ) ρ 2 ) ∗ w ( ρ ) = 0 {\displaystyle {\frac {d^{2}w(\rho )}{d\rho ^{2}}}+(1-{\frac {2\eta }{\rho }}-{\frac {l*(l+1)}{\rho ^{2}}})*w(\rho )=0}
此方程的两个解为:
F ℓ ( η , ρ ) {\displaystyle F_{\ell }(\eta ,\rho )} 和 G ℓ ( η , ρ ) {\displaystyle G_{\ell }(\eta ,\rho )} , 以 合流超几何函数表示