I'm starting to work with DDSCAT (http://www.astro.princeton.edu/~draine/DDSCAT.html). In the examples there structures standards. But still do not understand how I can create new structures and what software to use it. I need to create a cluster of nanoparticles.
Hi,
As you've mentioned there are predefined geometries in the DDSCAT package.
One of them SPHERES_N describes a cluster of N spheres of single isotropic material. You'll have to define the sets of coordinates and sizes for each particle in the cluster in the .par file, though. If you want the particles in the cluster to be of different composition, you should use SPH_ANI_N target. Of course, there is an option to to construct the target yourself by editing the shape.dat file as described in the Manual and setting 'FROM_FILE' option for the 'target' but this is a troublesome task.
If somebody made a program to facilitate the construction of 'shape' file, I would like to know about it, too. :)
Hope this helps!
D.
thanks for the comment.
I found two sources that mentions about the construction and modification of targets. The first is a master's thesis (http://trace.tennessee.edu/utk_gradthes/961/), where the appendix shows how the structures were generated. He used the matlab code, but not easy to build something more specific. The second, more interesting from a practical point of view, is the dissertation of Jain, PK (http://smartech.gatech.edu/handle/1853/28207), in Appendix A where he describes his procedure. According to him, "All the standard shape definition (target.out) That files need to be combined are imported into an Origin (Originlab I suppose) worksheet. Different shapes The Can Be moved, rotated, or truncated along any of the dimensions by use of Single Origin add, multiply or subtract operations on the X, Y, Z columns. Very basic knowledge of vectors helps to determine the operation to be used. Once the shape is custom built, it can be plotted in 3-D to verify accuracy, Which Following the worksheet can be exported into the shape.dat file. ". But so far I could not successfully plotting the target. If anyone knows the steps, please comment.
One can use Blender open source software to create the geometry then export the target to .obj file. (using triangles). Once that is done use the ddaconvert tool available from the nanoBIO node at nanoHUB.org
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