Classes‎ > ‎458‎ > ‎

GULP output

Let's go through the most important parts of the GULP output file, for the example of one of the vacancy supercell calculations:

Formula = Au255

Check to make sure that you simulated what you wanted to! Examining this line indicates that the input files we created already included a vacancy.

Cartesian lattice vectors (Angstroms) :

       16.312068    0.000000    0.000000
        0.000000   16.312068    0.000000
        0.000000    0.000000   16.312068

  Cell parameters (Angstroms/Degrees):

  a =      16.3121    alpha =  90.0000
  b =      16.3121    beta  =  90.0000
  c =      16.3121    gamma =  90.0000

Crystallographic information. This simple case shows that we have a cubic cell that is 4 fcc Au conventional cells on each side.

--------------------------------------------------------------------------------
   No.  Atomic       x           y          z         Charge      Occupancy
        Label      (Frac)      (Frac)     (Frac)        (e)         (Frac)
--------------------------------------------------------------------------------
      1 Au    c    0.000000    0.000000    0.250000      0.0000    1.000000
      2 Au    c    0.000000 *  0.000000 *  0.500000 *    0.0000    1.000000
      3 Au    c    0.000000 *  0.000000 *  0.750000 *    0.0000    1.000000
etc...

Fractional coordinates of all the atoms in the simulation.

--------------------------------------------------------------------------------
Atom  Types   Potential         A         B         C         D     Cutoffs(Ang)
  1     2                                                            Min    Max
--------------------------------------------------------------------------------
Au   c Au   c Lennard 12  6 0.214E+06  625.     0.00      0.00      0.000 40.000
--------------------------------------------------------------------------------

The potential parameters we are using, which of course come directly from the input file.

  Start of bulk optimisation :

  Cycle:      0 Energy:      -998.396806  Gnorm:      0.033248  CPU:    1.590
  ** Hessian calculated **
  Cycle:      1 Energy:      -998.451903  Gnorm:      0.000832  CPU:    4.020
  Cycle:      2 Energy:      -998.451930  Gnorm:      0.000025  CPU:    5.810


  **** Optimisation achieved ****

If we set "opti" in our input file, GULP will iteratively minimize the energy of the system by relaxing atomic coordinates. Notice how the energy drops after each iteration.

 Total lattice energy       =        -998.45192969 eV

Our final energy: the most important number in the output file!

Comments