# Changeset f224873 in sasmodels

Ignore:
Timestamp:
Jul 25, 2015 7:29:44 PM (7 years ago)
Branches:
master, core_shell_microgels, costrafo411, magnetic_model, release_v0.94, release_v0.95, ticket-1257-vesicle-product, ticket_1156, ticket_1265_superball, ticket_822_more_unit_tests
Children:
346bc88
Parents:
f3f46cd
Message:

updated documentation - see ticket #400

File:
1 edited

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Unmodified
 r3e428ec ---------- Calculates the scattering from a randomly distributed, two-phase system based on the Debye-Anderson-Brumberger (DAB) model for such systems. The two-phase system is characterized by a single length scale, the correlation length, which is a measure of the average spacing between regions of phase 1 and phase 2. **The model also assumes smooth interfaces** **between the phases** and hence exhibits Porod behavior (I ~ *q*\ :sup:-4) at large *q* (*QL* >> 1). Calculates the scattering from a randomly distributed, two-phase system based on the Debye-Anderson-Brumberger (DAB) model for such systems. The two-phase system is characterized by a single length scale, the correlation length, which is a measure of the average spacing between regions of phase 1 and phase 2. **The model also assumes smooth interfaces between the phases** and hence exhibits Porod behavior (I ~ *q*\ :sup:-4) at large *q* (*QL* >> 1). The DAB model is ostensibly a development of the earlier Debye-Bueche model. .. figure:: img/dab_1d.jpg *Definition* .. math:: I(q) = \text{scale}\cdot\frac{L^3}{(1 + (q L)^2)^2} + \text{background} .. math:: I(q) = \text{scale}\cdot\frac{L^3}{(1 + (q \cdot L)^2)^2} + \text{background} where scale is .. math:: \text{scale} = 8 \pi \phi (1-\phi)(\Delta \rho)^2 and the parameter *L* is the correlation length. For 2D data: The 2D scattering intensity is calculated in the same way as 1D, where the *q* vector is defined as .. math:: q = \sqrt{q_x^2 + q_y^2} ==============  ========  ============= Parameter name  Units     Default value ==============  ========  ============= scale           None      1.0 corr length L   |Ang|     50.0 background      |cm^-1|   0.0 ==============  ========  ============= .. figure:: img/dab_1d.jpg 1D plot using the default values (w/200 data point). Reference --------- P Debye, H R Anderson, H Brumberger, *Scattering by an Inhomogeneous Solid. II. The Correlation Function* *and its Application*, *J. Appl. Phys.*, 28(6) (1957) 679 P Debye, H R Anderson, H Brumberger, *Scattering by an Inhomogeneous Solid. II. The Correlation Function and its Application*, *J. Appl. Phys.*, 28(6) (1957) 679 P Debye, A M Bueche, *Scattering by an Inhomogeneous Solid*, *J. Appl. Phys.*, 20 (1949) 518 P Debye, A M Bueche, *Scattering by an Inhomogeneous Solid*, *J. Appl. Phys.*, 20 (1949) 518 *2013/09/09 - Description reviewed by King, S and Parker, P.* description = """\ F(q)= L^3/(1 + (q*L)^2)^2 F(q)= scale * L^3/(1 + (q*L)^2)^2 L: the correlation length