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--- documentation:element_specific_model [2015/09/09 08:51] – macke
+++ documentation:element_specific_model [2015/11/30 10:45] (current) – macke
@@ Line 1: / Line 1: @@
-=== Element Specific Modelling ===
+===== Element Specific Modelling =====
-The standard modelling of thin films is done in the layer table and consists of a list of layers of different compound materials. A compound here is defined as a group of elements which have a homogeneous density inside the layer (e. g. crystals, same bondings). The optical constants can be achieved by a linear combination of element-specific scattering tensors (e. g. off-resonant Chantler-tables).
+The standard modelling of thin films is done in the layer table and consists of a list of layers of different compound materials. A compound here is defined as a group of elements which have a homogeneous density inside the layer (e. g. crystals). The optical constants can be achieved by a linear combination of element-specific scattering factors (e. g. off-resonant Chantler-tables).
 The main parameters for each layer are the thickness, interface roughnesses and the optical constants.
-If the density or the bondings change (e. g. by strain, oxidation, contaminations) you have to introduce additonal layers with correct assumptions about the properties of the layer.
+If the properties of the compound change (e. g. by strain, oxidation, contaminations) you have to introduce additonal layers with assumptions about the properties of the layer.
-The element-specific idea is to introduce an advanced way of modelling the layer. The main assumption is that you have seperated layer profiles for each element. In contrast to the material-modelling the parameters for each element specific layer are the element densities, the element interface roughnesses. Each element has their own scattering factors f1, f2
+The element-specific idea is to introduce an advanced way of modelling the layer. The main assumption is that you have seperated layer profiles for each element. In contrast to the compound-modelling the parameters for each element specific layer are the element densities, thicknesses and the element interface roughnesses. Each element has their own scattering factors f1, f2.
 === Activating Element Mode ===
-At the moment there is only one way to initially change to element mode. After the initialization step the mode change can be done in the menu under "mode".
+At the moment there is only one way to initially change to element mode. After the initialization step the change of the mode can be done in the menu under "mode".
-The first steps you have to do are in the layer tables. Introduce the initial layer configuration  and begin to make a "coarse" fit of the system. (coarse means: as good as possible)
+. Work in the compound mode. Introduce the initial layer configuration and begin to make a "coarse" fit of the system. (coarse means: as good as possible)
-The second step is to type in the initial material density [g/cm^3] and the chemical formula in the properties dialog for each layer (Right Click->Properties).
+.
+Type in the initial material density [g/cm^3] and the chemical formula in the properties dialog for each layer (Right Click->Properties).
 E. g.
   * "Si" (Silicium)
@@ Line 22: / Line 23: @@
   * "SiO2C0" Oxidized Silicium with possible Carbon contamination.
+.
 In the final step  you have to go to the Optical Constants Frame in the Data register and start the converter by clicking the button "Material to Element". You are in element mode now.
-The conversion algorithm uses an internal database to get the molare mass of each element.
+The conversion algorithm uses an internal database to get the molar mass of each element.
 === Using Element Mode ===
-The most important additional options for the element mode are in the "Optical Constants" Frame in the "Data" Register. Here you can change the active element for the layer table.
+The most important additional options for the element mode are in the "Element Mode" Frame in the "Data" Register. Here you can change the active element for the layer table. The layer table is different for each element and consists of the entries thickness in Angstrom, density in mol/cm^3, and roughness in Angstrom. The scattering factors f1/f2 are the same for each element.
-The layer table is different for each element and consists of the entries thickness in Angstrom, density in mol/cm^3, roughness in Angstrom. The scattering factors f1/f2 are the same for each element.
-Additional you can display the element specific profiles and f1/f2 for each element.
-Instead of .db files the program needs .ff files for the scattering factors. E. g. Ni.ff, H.ff, .....
-Fitting works like in compound mode.
+  - Additional you can display the element specific profiles and f1/f2 for each element.
+  - Instead of .db files the program needs .ff files for the scattering factors. E. g. Ni.ff, H.ff, .....
+  - Fitting works like in compound mode.
 The current version has following limitations
-  - after initialization step no additional element types can be added
+  - After initialization step no additional element types can be added
-  - In total eight different elements are supported. Otherwise the display of the profiles will not work.
+  - In total eight different elements are supported. Otherwise the display of the element density profiles will not work.
 === What is the strength of this element mode? (Valency, Magnetic profiles, ...)===