documentation:element_specific_model
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- | === 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 | + | 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 |
The main parameters for each layer are the thickness, interface roughnesses and the optical constants. | The main parameters for each layer are the thickness, interface roughnesses and the optical constants. | ||
- | If the density or the bondings | + | If the properties of the compound |
- | 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, |
=== Activating Element Mode === | === 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 " | + | At the moment there is only one way to initially change to element mode. After the initialization step the change |
- | The first steps you have to do are in the layer tables. Introduce the initial layer configuration | + | 1. Work in the compound mode. Introduce the initial layer configuration and begin to make a " |
- | 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-> | + | 2. |
+ | Type in the initial material density [g/cm^3] and the chemical formula in the properties dialog for each layer (Right Click-> | ||
E. g. | E. g. | ||
* " | * " | ||
Line 22: | Line 23: | ||
* " | * " | ||
+ | 3. | ||
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 " | 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 " | ||
- | The conversion algorithm uses an internal database to get the molare | + | The conversion algorithm uses an internal database to get the molar mass of each element. |
=== Using Element Mode === | === Using Element Mode === | ||
- | The most important additional options for the element mode are in the "Optical Constants" Frame in the " | + | The most important additional options for the element mode are in the "Element Mode" Frame in the " |
- | 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. | + | - 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. | ||
- | Instead of .db files the program needs .ff files for the scattering factors. E. g. Ni.ff, H.ff, ..... | + | The current version has following limitations |
- | Fitting works like in compound mode. | + | - After initialization step no additional element types can be added |
+ | - 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, ...)=== | ||
- | The current version has following limitations | + | The strength of of the element mode lies in the fact you can choose completely different profiles for each " |
- | - after initialization step no additional element types can be added | + | For example if an element has different valency in one system the on-resonant scattering factors might change. To take into account such systems different valencies can be introduced by an additional element. This should work straight forward. You can choose an arbitrary additional element. |
- | - In total eight different elements are supported. Otherwise the display of the profiles will not work. | + | |
- | + | ||
- | === Different valencies === | + | |
- | + | ||
- | If an element has different valency in one system the on-resonant scattering factors might change. To take into account such systems different valencies can be introduced by an additional element. This should work straight forward. You can choose an arbitrary additional element. | + | |
For example you can introduce " | For example you can introduce " | ||
+ | The other possibility is to use a element just for the magnetic profile. This means, that for this element the scattering factor f is set to zero and only the magnetic scattering factor fm is unequal zero. The " | ||
documentation/element_specific_model.1420023890.txt.gz · Last modified: 2014/12/31 11:04 by macke