1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
|
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" lang="en">
<head>
<title>GAMGI Tutorials: Interstices in the CFC structure</title>
<link rel="icon" type="image/png" href="../icon/gamgi16.png"/>
<link rel="stylesheet" type="text/css" href="../css/base.css"/>
<link rel="stylesheet" type="text/css" href="../css/notebook.css"/>
</head>
<body>
<h1>Interstices in the CFC structure</h1>
<div id="notebook">
<ul>
<li><a href="interstices_cfc_page1.html">Page 1</a></li>
<li><span>Page 2</span></li>
</ul>
</div>
<div class="contents">
<h3>Tetrahedral interstices</h3>
<ol>
<li>
Press <b>Cell->Remove</b> and click the mouse over the cell, to remove it.
Otherwise, just scale it down and move it away from the center, to economize
space. This way, the two cells containing octahedral and tetrahedral
interstices can be compared later.
</li>
<li>
Press <b>Cell->Create</b> and set <b>System</b> to <b>c</b>,
<b>Lattice</b> to <b>F</b> (Face-Centered Cubic) and <b>a</b>
to <b>2.828</b> (so the structural atoms will be in contact
along <110> directions). Press <b>Ok</b> to create the cell.
</li>
<li>
Press <b>Atom->Modify</b> and click the mouse over the interstitial
atom, to select it. Change its <b>Radius</b> to <b>0.225</b>, the size
of the CFC tetrahedral interstices and press <b>Ok</b>.
</li>
<li>
Press <b>Cell->Link</b> and select the <b>Crystal</b> link method.
Press the mouse over the cell, and then over the interstitial atom,
to identify the objects to link. Set <b>x</b>, <b>y</b>, <b>z</b>
coordinates (<b>Position</b> page) to <b>0.25</b>, <b>0.25</b>,
<b>0.25</b> and press <b>Ok</b>. 4 interstitial atoms are now visible,
corresponding to 4 interstices inside the cell or 1/2 of the tetrahedral
interstices available.</li>
<li>
Repeat the procedure above with <b>x</b>, <b>y</b>, <b>z</b> coordinates set
to <b>0.75</b>, <b>0.75</b>, <b>0.75</b> to allocate the remaining interstices.
8 interstitial atoms are now visible, centered in the octant cubes, corresponding
to a total of 8 tetrahedral interstices inside the cell.
</li>
<li>
To represent the structural atoms, repeat the linking procedure above,
but this time pressing the mouse over the Cu structural atom, to identify
the linked atom, and setting <b>x</b>, <b>y</b>, <b>z</b> coordinates
to <b>0.0</b>, <b>0.0</b>, <b>0.0</b>. 14 structural atoms are now visible,
8 in the vertices and 6 centered in the faces, corresponding to a total
of 4 atoms inside the cell.
</li>
<li>
To remove the Cu,C atoms used as models during the building process,
press <b>Atom->Remove</b> and click the mouse over them.
</li>
<li>
Rotate,move,scale the cell with the mouse. To have a better view inside
the cell, remove some of the structural atoms outside. Select
<b>Atom->Remove</b> and press the mouse over the atoms to remove.
</li>
</ol>
</div>
<div id="bottom">
<a href="../index.shtml">Home</a>
</div>
</body>
</html>
|
