Core shell nanoparticles

Scattering from cuboidal core-shell particles.

  • The sample is made of core-shell particles whose outer and inner shells are boxes with dimensions $L_1 = W_1 = 16$ nm, $H_1 = 8$ nm and $L_2 = W_2 = 12$ nm, $H_2 = 7$ nm, respectively, where $L_i$, $W_i$ and $H_i$ are the length, width and height of box $i$.
  • The smaller box is positioned so that the centres of the bottom faces of both particles coincide.
  • The simulation is run using the Born approximation. There is no substrate and no interference between the different scattered beams.
  • The planar distribution of the particles is diluted and random.
  • The incident wavelength is equal to $1$ $\unicode{x212B}$.
  • The incident angles are $\alpha_i = 0.2 ^{\circ}$ and $\varphi_i = 0^{\circ}$.

Real-space model

Intensity image

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#!/usr/bin/env python3
"""
Core shell nanoparticles
"""
import bornagain as ba
from bornagain import deg, nm


def get_sample():
    """
    Returns a sample with box-shaped core-shell particles on a substrate.
    """

    # Define materials
    material_Core = ba.HomogeneousMaterial("Core", 6e-05, 2e-08)
    material_Shell = ba.HomogeneousMaterial("Shell", 0.0001, 2e-08)
    material_Vacuum = ba.HomogeneousMaterial("Vacuum", 0.0, 0.0)

    # Define form factors
    ff_1 = ba.FormFactorBox(12.0*nm, 12.0*nm, 7.0*nm)
    ff_2 = ba.FormFactorBox(16.0*nm, 16.0*nm, 8.0*nm)

    # Define particles
    particle_1 = ba.Particle(material_Core, ff_1)
    particle_2 = ba.Particle(material_Shell, ff_2)

    # Define core shell particles
    particle_3 = ba.ParticleCoreShell(particle_2, particle_1)

    # Define interference functions
    iff = ba.InterferenceFunctionNone()

    # Define particle layouts
    layout = ba.ParticleLayout()
    layout.addParticle(particle_3, 1.0)
    layout.setInterferenceFunction(iff)
    layout.setWeight(1)
    layout.setTotalParticleSurfaceDensity(0.01)

    # Define layers
    layer = ba.Layer(material_Vacuum)
    layer.addLayout(layout)

    # Define sample
    sample = ba.MultiLayer()
    sample.addLayer(layer)

    return sample


def get_simulation(sample):
    beam = ba.Beam(1.0, 0.1*nm, ba.Direction(0.2*deg, 0*deg))
    detector = ba.SphericalDetector(200, 2*deg, 0*deg, 1*deg)
    simulation = ba.GISASSimulation(beam, sample, detector)
    return simulation


if __name__ == '__main__':
    import ba_plot
    sample = get_sample()
    simulation = get_simulation(sample)
    ba_plot.run_and_plot(simulation)
CoreShellNanoparticles.py