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33 Coulomb FunctionsVariables \rho,\eta

Β§33.13 Complex Variable and Parameters

The functions F_{\ell}\left(\eta,\rho\right), G_{\ell}\left(\eta,\rho\right), and {H^{\pm}_{\ell}}\left(\eta,\rho\right) may be extended to noninteger values of \ell by generalizing (2\ell+1)!=\Gamma\left(2\ell+2\right), and supplementing (33.6.5) by a formula derived from (33.2.8) with U\left(a,b,z\right) expanded via (13.2.42).

These functions may also be continued analytically to complex values of \rho, \eta, and \ell. The quantities C_{\ell}\left(\eta\right), {\sigma_{\ell}}\left(\eta\right), and R_{\ell}, given by (33.2.6), (33.2.10), and (33.4.1), respectively, must be defined consistently so that

and

For further information see Dzieciol et al. (1999), Thompson and Barnett (1986), and Humblet (1984).