source: sasview/sansmodels/src/sans/models/c_extensions/lamellar.h @ 8e91f01

#if !defined(lamellar_h)
#define lamellar_h
/** Structure definition for lamellar parameters
 * [PYTHONCLASS] = LamellarModel
   [DESCRIPTION] = <text>[Dilute Lamellar Form Factor](from a lyotropic lamellar phase)
           I(q)= 2*pi*P(q)/(delta *q^(2)), where
                P(q)=2*(contrast/q)^(2)*(1-cos(q*delta)
                *e^(1/2*(q*sigma)^(2)).
                delta = bilayer thickness
                sigma = variation in bilayer thickness
                        = delta*polydispersity
                contrast = SLD_solvent - SLD_bilayer
        Note: the polydispersity in delta is included.
 </text>
 **/
typedef struct {
    /// Scale factor
    //  [DEFAULT]=scale=1.0
    double scale;
    /// delta bilayer thickness [A]
    //  [DEFAULT]=delta=50.0 [A]
    double delta;
    /// variation in bilayer thickness
    //  [DEFAULT]=sigma=0.15
    double sigma;
    /// Contrast [1/A²]
    //  [DEFAULT]=contrast=5.3e-6 [1/A²]
    double contrast;
        /// Incoherent Background [1/cm] 0.00
        //  [DEFAULT]=background=0.0 [1/cm]
        double background;


} LamellarParameters;



/// 1D scattering function
double lamellar_analytical_1D(LamellarParameters *pars, double q);

/// 2D scattering function
double lamellar_analytical_2D(LamellarParameters *pars, double q, double phi);
double lamellar_analytical_2DXY(LamellarParameters *pars, double qx, double qy);
double lamellar_analytical_2D_scaled(LamellarParameters *pars, double q, double q_x, double q_y);

#endif