1 @cindex Coulomb wave functions
4 The prototypes of the Coulomb functions are declared in the header file
5 @file{gsl_sf_coulomb.h}. Both bound state and scattering solutions are
9 * Normalized Hydrogenic Bound States::
10 * Coulomb Wave Functions::
11 * Coulomb Wave Function Normalization Constant::
14 @node Normalized Hydrogenic Bound States
15 @subsection Normalized Hydrogenic Bound States
17 @deftypefun double gsl_sf_hydrogenicR_1 (double @var{Z}, double @var{r})
18 @deftypefunx int gsl_sf_hydrogenicR_1_e (double @var{Z}, double @var{r}, gsl_sf_result * @var{result})
19 These routines compute the lowest-order normalized hydrogenic bound
20 state radial wavefunction @c{$R_1 := 2Z \sqrt{Z} \exp(-Z r)$}
21 @math{R_1 := 2Z \sqrt@{Z@} \exp(-Z r)}.
24 @deftypefun double gsl_sf_hydrogenicR (int @var{n}, int @var{l}, double @var{Z}, double @var{r})
25 @deftypefunx int gsl_sf_hydrogenicR_e (int @var{n}, int @var{l}, double @var{Z}, double @var{r}, gsl_sf_result * @var{result})
26 These routines compute the @var{n}-th normalized hydrogenic bound state
32 R_n := {2 Z^{3/2} \over n^2} \left({2Z r \over n}\right)^l \sqrt{(n-l-1)! \over (n+l)!} \exp(-Z r/n) L^{2l+1}_{n-l-1}(2Z r / n).
39 R_n := 2 (Z^@{3/2@}/n^2) \sqrt@{(n-l-1)!/(n+l)!@} \exp(-Z r/n) (2Zr/n)^l
40 L^@{2l+1@}_@{n-l-1@}(2Zr/n).
45 where @math{L^a_b(x)} is the generalized Laguerre polynomial (@pxref{Laguerre Functions}).
46 The normalization is chosen such that the wavefunction @math{\psi} is
48 @c{$\psi(n,l,r) = R_n Y_{lm}$}
49 @math{\psi(n,l,r) = R_n Y_@{lm@}}.
52 @node Coulomb Wave Functions
53 @subsection Coulomb Wave Functions
55 The Coulomb wave functions @math{F_L(\eta,x)}, @math{G_L(\eta,x)} are
56 described in Abramowitz & Stegun, Chapter 14. Because there can be a
57 large dynamic range of values for these functions, overflows are handled
58 gracefully. If an overflow occurs, @code{GSL_EOVRFLW} is signalled and
59 exponent(s) are returned through the modifiable parameters @var{exp_F},
60 @var{exp_G}. The full solution can be reconstructed from the following
66 F_L(\eta,x) &= fc[k_L] * \exp(exp_F)\cr
67 G_L(\eta,x) &= gc[k_L] * \exp(exp_G)\cr
69 F_L'(\eta,x) &= fcp[k_L] * \exp(exp_F)\cr
70 G_L'(\eta,x) &= gcp[k_L] * \exp(exp_G)
78 F_L(eta,x) = fc[k_L] * exp(exp_F)
79 G_L(eta,x) = gc[k_L] * exp(exp_G)
81 F_L'(eta,x) = fcp[k_L] * exp(exp_F)
82 G_L'(eta,x) = gcp[k_L] * exp(exp_G)
88 @deftypefun int gsl_sf_coulomb_wave_FG_e (double @var{eta}, double @var{x}, double @var{L_F}, int @var{k}, gsl_sf_result * @var{F}, gsl_sf_result * @var{Fp}, gsl_sf_result * @var{G}, gsl_sf_result * @var{Gp}, double * @var{exp_F}, double * @var{exp_G})
89 This function computes the Coulomb wave functions @math{F_L(\eta,x)},
91 @math{G_@{L-k@}(\eta,x)} and their derivatives
93 @c{$G'_{L-k}(\eta,x)$}
94 @math{G'_@{L-k@}(\eta,x)}
95 with respect to @math{x}. The parameters are restricted to @math{L,
96 L-k > -1/2}, @math{x > 0} and integer @math{k}. Note that @math{L}
97 itself is not restricted to being an integer. The results are stored in
98 the parameters @var{F}, @var{G} for the function values and @var{Fp},
99 @var{Gp} for the derivative values. If an overflow occurs,
100 @code{GSL_EOVRFLW} is returned and scaling exponents are stored in
101 the modifiable parameters @var{exp_F}, @var{exp_G}.
104 @deftypefun int gsl_sf_coulomb_wave_F_array (double @var{L_min}, int @var{kmax}, double @var{eta}, double @var{x}, double @var{fc_array}[], double * @var{F_exponent})
105 This function computes the Coulomb wave function @math{F_L(\eta,x)} for
106 @math{L = Lmin \dots Lmin + kmax}, storing the results in @var{fc_array}.
107 In the case of overflow the exponent is stored in @var{F_exponent}.
110 @deftypefun int gsl_sf_coulomb_wave_FG_array (double @var{L_min}, int @var{kmax}, double @var{eta}, double @var{x}, double @var{fc_array}[], double @var{gc_array}[], double * @var{F_exponent}, double * @var{G_exponent})
111 This function computes the functions @math{F_L(\eta,x)},
112 @math{G_L(\eta,x)} for @math{L = Lmin \dots Lmin + kmax} storing the
113 results in @var{fc_array} and @var{gc_array}. In the case of overflow the
114 exponents are stored in @var{F_exponent} and @var{G_exponent}.
117 @deftypefun int gsl_sf_coulomb_wave_FGp_array (double @var{L_min}, int @var{kmax}, double @var{eta}, double @var{x}, double @var{fc_array}[], double @var{fcp_array}[], double @var{gc_array}[], double @var{gcp_array}[], double * @var{F_exponent}, double * @var{G_exponent})
118 This function computes the functions @math{F_L(\eta,x)},
119 @math{G_L(\eta,x)} and their derivatives @math{F'_L(\eta,x)},
120 @math{G'_L(\eta,x)} for @math{L = Lmin \dots Lmin + kmax} storing the
121 results in @var{fc_array}, @var{gc_array}, @var{fcp_array} and @var{gcp_array}.
122 In the case of overflow the exponents are stored in @var{F_exponent}
123 and @var{G_exponent}.
126 @deftypefun int gsl_sf_coulomb_wave_sphF_array (double @var{L_min}, int @var{kmax}, double @var{eta}, double @var{x}, double @var{fc_array}[], double @var{F_exponent}[])
127 This function computes the Coulomb wave function divided by the argument
128 @math{F_L(\eta, x)/x} for @math{L = Lmin \dots Lmin + kmax}, storing the
129 results in @var{fc_array}. In the case of overflow the exponent is
130 stored in @var{F_exponent}. This function reduces to spherical Bessel
131 functions in the limit @math{\eta \to 0}.
134 @node Coulomb Wave Function Normalization Constant
135 @subsection Coulomb Wave Function Normalization Constant
137 The Coulomb wave function normalization constant is defined in
140 @deftypefun int gsl_sf_coulomb_CL_e (double @var{L}, double @var{eta}, gsl_sf_result * @var{result})
141 This function computes the Coulomb wave function normalization constant
142 @math{C_L(\eta)} for @math{L > -1}.
145 @deftypefun int gsl_sf_coulomb_CL_array (double @var{Lmin}, int @var{kmax}, double @var{eta}, double @var{cl}[])
146 This function computes the Coulomb wave function normalization constant
147 @math{C_L(\eta)} for @math{L = Lmin \dots Lmin + kmax}, @math{Lmin > -1}.