source: sasmodels/model/broad_peak.html @ 68532f3

gh-pages
Last change on this file since 68532f3 was 68532f3, checked in by ajj, 8 years ago

Adding docs

  • Property mode set to 100644
File size: 5.5 KB
Line 
1<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
2  "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
3
4
5<html xmlns="http://www.w3.org/1999/xhtml">
6  <head>
7    <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
8   
9    <title>2.2.1. Broad peak &mdash; Sasmodels</title>
10   
11    <link rel="stylesheet" href="../_static/haiku-site.css" type="text/css" />
12    <link rel="stylesheet" href="../_static/pygments.css" type="text/css" />
13   
14    <script type="text/javascript">
15      var DOCUMENTATION_OPTIONS = {
16        URL_ROOT:    '../',
17        VERSION:     '0.9',
18        COLLAPSE_INDEX: false,
19        FILE_SUFFIX: '.html',
20        HAS_SOURCE:  true
21      };
22    </script>
23    <script type="text/javascript" src="../_static/jquery.js"></script>
24    <script type="text/javascript" src="../_static/underscore.js"></script>
25    <script type="text/javascript" src="../_static/doctools.js"></script>
26    <script type="text/javascript" src="http://cdn.mathjax.org/mathjax/latest/MathJax.js?config=TeX-AMS-MML_HTMLorMML"></script>
27    <link rel="top" title="Sasmodels" href="../index.html" />
28    <link rel="up" title="2.2. Shape-Independent Functions" href="../ref/models/shape-independent.html" />
29    <link rel="next" title="2.2.2. Dab" href="dab.html" />
30    <link rel="prev" title="2.2. Shape-Independent Functions" href="../ref/models/shape-independent.html" /> 
31  </head>
32  <body>
33      <div class="header"><h1 class="heading"><a href="../index.html">
34          <span>Home</span></a></h1>
35        <h2 class="heading"><span>2.2.1. Broad peak</span></h2>
36      </div>
37      <div class="topnav">
38     
39        <p>
40        «&#160;&#160;<a href="../ref/models/shape-independent.html">2.2. Shape-Independent Functions</a>
41        &#160;&#160;::&#160;&#160;
42        <a class="uplink" href="../index.html">Contents</a>
43        &#160;&#160;::&#160;&#160;
44        <a href="dab.html">2.2.2. Dab</a>&#160;&#160;»
45        </p>
46
47      </div>
48      <div class="content">
49       
50       
51  <div class="section" id="broad-peak">
52<span id="id1"></span><h1>2.2.1. Broad peak<a class="headerlink" href="#broad-peak" title="Permalink to this headline">¶</a></h1>
53<p>Broad Lorentzian type peak on top of a power law decay</p>
54<table border="1" class="docutils">
55<colgroup>
56<col width="19%" />
57<col width="52%" />
58<col width="11%" />
59<col width="18%" />
60</colgroup>
61<thead valign="bottom">
62<tr class="row-odd"><th class="head">Parameter</th>
63<th class="head">Description</th>
64<th class="head">Units</th>
65<th class="head">Default value</th>
66</tr>
67</thead>
68<tbody valign="top">
69<tr class="row-even"><td>scale</td>
70<td>Source intensity</td>
71<td>None</td>
72<td>1</td>
73</tr>
74<tr class="row-odd"><td>background</td>
75<td>Source background</td>
76<td>cm<sup>-1</sup></td>
77<td>0</td>
78</tr>
79<tr class="row-even"><td>porod_scale</td>
80<td>Power law scale factor</td>
81<td>None</td>
82<td>1e-05</td>
83</tr>
84<tr class="row-odd"><td>porod_exp</td>
85<td>Exponent of power law</td>
86<td>None</td>
87<td>3</td>
88</tr>
89<tr class="row-even"><td>lorentz_scale</td>
90<td>Scale factor for broad Lorentzian peak</td>
91<td>None</td>
92<td>10</td>
93</tr>
94<tr class="row-odd"><td>lorentz_length</td>
95<td>Lorentzian screening length</td>
96<td>Å</td>
97<td>50</td>
98</tr>
99<tr class="row-even"><td>peak_pos</td>
100<td>Peak postion in q</td>
101<td>Å<sup>-1</sup></td>
102<td>0.1</td>
103</tr>
104<tr class="row-odd"><td>lorentz_exp</td>
105<td>exponent of Lorentz function</td>
106<td>None</td>
107<td>2</td>
108</tr>
109</tbody>
110</table>
111<p>The returned value is scaled to units of cm<sup>-1</sup>.</p>
112<p>This model calculates an empirical functional form for SAS data characterized
113by a broad scattering peak. Many SAS spectra are characterized by a broad peak
114even though they are from amorphous soft materials. For example, soft systems
115that show a SAS peak include copolymers, polyelectrolytes, multiphase systems,
116layered structures, etc.</p>
117<p>The d-spacing corresponding to the broad peak is a characteristic distance
118between the scattering inhomogeneities (such as in lamellar, cylindrical, or
119spherical morphologies, or for bicontinuous structures).</p>
120<p>The returned value is scaled to units of cm<sup>-1</sup>, absolute scale.</p>
121<div class="section" id="definition">
122<h2>2.2.1.1. Definition<a class="headerlink" href="#definition" title="Permalink to this headline">¶</a></h2>
123<p>The scattering intensity <em>I(q)</em> is calculated as</p>
124<p>Here the peak position is related to the d-spacing as <em>Q0</em> = 2|pi| / <em>d0</em>.</p>
125<p>For 2D data: The 2D scattering intensity is calculated in the same way as 1D,
126where the <em>q</em> vector is defined as</p>
127<img alt="model/img/image175.jpg" src="model/img/image175.jpg" />
128<p><em>Figure. 1D plot using the default values (w/200 data point).</em></p>
129</div>
130<div class="section" id="reference">
131<h2>2.2.1.2. REFERENCE<a class="headerlink" href="#reference" title="Permalink to this headline">¶</a></h2>
132<p>None.</p>
133<p><em>2013/09/09 - Description reviewed by King, S and Parker, P.</em></p>
134</div>
135</div>
136
137
138      </div>
139      <div class="bottomnav">
140     
141        <p>
142        «&#160;&#160;<a href="../ref/models/shape-independent.html">2.2. Shape-Independent Functions</a>
143        &#160;&#160;::&#160;&#160;
144        <a class="uplink" href="../index.html">Contents</a>
145        &#160;&#160;::&#160;&#160;
146        <a href="dab.html">2.2.2. Dab</a>&#160;&#160;»
147        </p>
148
149      </div>
150
151    <div class="footer">
152        &copy; Copyright 2014, sasview team.
153      Created using <a href="http://sphinx-doc.org/">Sphinx</a> 1.2.3.
154    </div>
155  </body>
156</html>
Note: See TracBrowser for help on using the repository browser.