XA Report, Introduction "Creating 4-7"

Introduction

Creating a pseudo orbital

  1. Without loss of generality we can assume that c[3] is equal to 1. Now we can solve the linear equation

    a    a         c         - x
     11   12        1           1
               *         = 
    a    a         c         - x
     21   22        2           2
    

    by using Gaussian Elimination.

  2. After having gained c[1] and c[2] we calculate:

       oo   2
    int    P   dr  =  y
       0    3S
    
  3. Normally y is not equal to 1.0 (as mentioned in our preconditions), because we previously set c[3] to 1.0). Therefore we have to normalize the solution by calculating:

            c              c              c
             1              2              3
    d   =  ----;   d   =  ----;   d   =  ----;
     1      y       2      y       3      y
    
  4. Finally, the new data values d[1], d[2] and d[3] of the pseudo orbital 3S are stored in the atom data structure.

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Reinhard Schaffner, © 1995-05-16