How to Get Started With Atomistic Simulations?
OR
How to Boost Your Existing Projects?

To Get started with "Atomistic simulations" you will need following:

• A computer
  A PC is sufficient for most projects. Any computer (MAC or UNIX workstations) with a DOS window can run ADESH.
  
• Adequate Software Package
  You may write the software yourself. In which case you will need to have compiler and programming capabilities, as well as thorough understanding of atomistic procedures.
  ** OR **
  Get a copy of ADESH
  
• Yourself and Some Time
  Armed with ADESH you can start getting meaningful results in about ONE DAY.
  
• CASA Engineering provides efficient technical support over the Internet and Phones.
• Look at the following example where you can make a computational cell and graphically view it. Just Download ADESH Demo version and follow the steps in this example.

HINTS TO USE ADESH:

• Use the arrow keys on the keyboard (up, down, left, right) to go to an option in ADESH's pull down menus.
• Do not use the mouse.
• Push (Enter) key to select an option.
• Push (Esc) key to escape from any window.
• Remember to go from left to write when you choose options. Always end with {Compute} option to implement your choices.
• You can make and view a computational cell by using following commands. To make simple cells of crystals with Unit Cells SC (Simple Cubic), BCC (Body Centered Cubic), FCC (Face Centered Cubic), DC (Diamond Cubic):Choose the following:
  
  Example: Silicon Cell

      {Unit Cell [ DC ] }
      {Atom [ Silicon ] }
      {Compute [ Make a computational cell ] }
      {File [ View < Y vS X > ] }
      (You will see a plot of Si cell)
  
      (For Aluminum cell, use FCC instead of DC
               and {Atom [ Aluminum ] }
  

   Example: Other Unit Cells
   { U. Cell [ User Defined 
   [ Position 1: (0.0, 0.0, 0.0) ]
   [ Position 2: (0.3333, 0.6667, 0.5) ] } Esc
   NOTE: Always input fractions less than 1.
  
  { Atom [ Ti ] }
  { AlloY [ Systematic 
       < Lattice Constant X ( 2.954 ) >
       < Lattice Constant Y ( 2.954 ) >
       < Lattice Constant Z ( 4.685 ) > 
       < Angle Gamma (X / Y) (120)  >
       < At ( 0, 0, 0 )  < Ti >  >
       < At ( 1/3, 2/3, 1/2 ) < Ti >  > ] }Esc
  { Compute [ Make the computational cell ( N ) ] }  
  View the cell:
  { suBset [ Plot < Slice > ] } Esc
  { File [ View < Y vs X > ] }
  NOTE: This will make an HCP cell
  You can also choose the option "HCP" to make the same cell.
  
  To make NaCl structure (TiC)
  
  Start ADESH
  { Unit Cell [ User Defined 
  < Position 1 ( 0, 0, 0)
              Position 2 (0.5, 0.5, 0)
              Position 3 (0, 0.5, 0.5)
              Position 4 (0.5, 0, 0.5)
              Position 5 (0.5, 0.5, 0.5)
              Position 6 (0.5, 0, 0)
              Position 7 (0, 0.5, 0)
             Position 8 (0, 0, 0.5) > ] } Esc
  
  { alloY [ Systematic 
  < Lattice Const. X : (4.33)
               Lattice Const. Y :(4.33)
               Lattice Const. Z :(4.33)
                At (0,   0,   0):( Ti )
                At (1/2, 1/2, 0):( Ti )
                At (0, 1/2, 1/2):( Ti )
                At (1/2, 0, 1/2):( Ti )
                At (1/2, 1/2, 1/2):( C )
                At (1/2,  0,  0) :( C )
                At (0,  1/2,  0) :( C )
                At (0,  0,  1/2) :( C ) > ] } Esc
  
  { Compute [ Make the computational cell ] } 
  ( 729 atoms )
  
  View the cell graphically
  
  { suBset [ Plot < Slice > ] } Esc
  { File [ View < Y vS X > ] }  
  { File [ View < Color code atoms 
                < Y vS X > ] }
  
   Default orientation of the cells:
   X (1 0 0), Y (0 1 0), Z(0 0 1)
   X is horizontal, Y is vertical,
   Z is perpendicular to the screen.
  
   You may change the Miller Indices using {M. Index} option. 
  
   More examples are in the manual. ASCII file "manual.asc" is
   enclosed with ADESH demo.
  
  

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anjali@casaengineering.com

Contact:
Anjali Nandedkar, Ph. D.
CASA Engineering
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Hopewell Junction
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Tel. and FAX: (845) 226 - 1925

anjali@casaengineering.com
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