source: sasview/sansmodels/src/sans/models/c_extensions/fcc.h @ 7a8faf8

#if !defined(fcc_h)
#define fcc_h

/**
 * Structure definition for FCC_ParaCrystal parameters
 */
 //[PYTHONCLASS] = FCCrystalModel
 //[DISP_PARAMS] = radius,phi, psi, theta
 //[DESCRIPTION] =<text>P(q)=(scale/Vp)*V_lattice*P(q)*Z(q)+bkg where scale is the volume
 //                                      fraction of sphere,
 //                             Vp = volume of the primary particle,
 //                             V_lattice = volume correction for
 //                                     for the crystal structure,
 //                             P(q)= form factor of the sphere (normalized),
 //                             Z(q)= paracrystalline structure factor
 //                                     for a face centered cubic structure.
 //                             [Face Centered Cubic ParaCrystal Model]
 //                             Parameters;
 //                             scale: volume fraction of spheres
 //                             bkg:background, R: radius of sphere
 //                             dnn: Nearest neighbor distance
 //                             d_factor: Paracrystal distortion factor
 //                             radius: radius of the spheres
 //                             sldSph: SLD of the sphere
 //                             sldSolv: SLD of the solvent
 //
 //             </text>
 //[FIXED]=  radius.width;phi.width;psi.width; theta.width
 //[ORIENTATION_PARAMS]= <text> phi;psi; theta; phi.width;psi.width; theta.width</text>

typedef struct {
    /// Scale factor
    //  [DEFAULT]=scale= 1.0
    double scale;

    /// Nearest neighbor distance [A]
    //  [DEFAULT]=dnn=220.0 [A]
    double dnn;

    /// Paracrystal distortion factor g
    //  [DEFAULT]=d_factor=0.06
    double d_factor;

    /// Radius of sphere [A]
    //  [DEFAULT]=radius=40.0 [A]
    double radius;

    /// sldSph [1/A^(2)]
    //  [DEFAULT]=sldSph= 3.0e-6 [1/A^(2)]
    double sldSph;

    /// sldSolv [1/A^(2)]
    //  [DEFAULT]=sldSolv= 6.3e-6 [1/A^(2)]
    double sldSolv;

        /// Incoherent Background [1/cm]
        //  [DEFAULT]=background=0 [1/cm]
        double background;
    /// Orientation of the a1 axis w/respect incoming beam [deg]
    //  [DEFAULT]=theta=0.0 [deg]
    double theta;
    /// Orientation of the a2 in the plane of the detector [deg]
    //  [DEFAULT]=phi=0.0 [deg]
    double phi;
    /// Orientation of the a3 in the plane of the detector [deg]
    //  [DEFAULT]=psi=0.0 [deg]
    double psi;

} FCParameters;



/// 1D scattering function
double fc_analytical_1D(FCParameters *pars, double q);

/// 2D scattering function
double fc_analytical_2D(FCParameters *pars, double q, double phi);
double fc_analytical_2DXY(FCParameters *pars, double qx, double qy);
double fc_analytical_2D_scaled(FCParameters *pars, double q, double q_x, double q_y);

#endif