
                         * SIMULATION KIT EXAMPLES *

This file contains notes on the example projects.

  DIRECTORY                  PROJECT DESCRIPTION
  =========================================================================
            |
  REFLECT   |  Ion reflection coefficients, 1 keV Ar -> Cu(100)
  NE-AG111  |  Sputter coefficient, 0.4 keV Ne -> Ag(111)
  ICISS     |  Impact collision ISS, 1.5 keV He -> Cu(110)
  MIXING    |  Recoil mixing in target, 0.5 keV Ar -> Cu(100)
  WINNOW    |  Sample output file for experimenting with Winnow + utils
            |
  =========================================================================

REFLECT directory
=================

This is a simple project which I used to estimate reflection
coefficients for 1 keV Ar incident on Cu(100) along a [011]
azimuth.

I ran 3 simulations of 1250 runs each, setting the projectile
altitudinal angle (in reflect.run) respectively to 30, 50 and
90 (normal) degrees respectively. The time per simulation was
about 3 hours.

The projectile's dynamical variables were recorded at the termination
of each simulation (set to 80 fs).

To count the number of reflected projectiles I used a filter
condition in Winnow: [rz > 1.0E-10] & [vz > 0.0], meaning only those
projectiles that were  > 1 A above the surface with positive velocities
were to be stored in the output file.

The reflection coefficient (R) can then be obtained by comparing the
file sizes before and after filtering. The results for 3 three angles
are compared to the BCA calculations by Hou and Robinson, Nuclear Instr.
Meth. 132 (1976) 641 in the table below.

Altitudinal
Angle (deg.)   R (Snook)    R (Hou & Rob.)
===========================================
90             0.078        0.06
50             0.184        0.20
30             0.580        0.62
===========================================


NE-AG111 directory
==================

This is a compact, but realistic, example of how you would go about
estimating a sputter coefficient for the system: 0.4 keV Ne incident
normally on a Ag(111) surface.

The results from this example are discussed in the Simulation Primer
(simprimr.doc) that ships with the SK files.

The target consists of 376 atoms. The simulations terminate after 400 fs,
or when the fastest lattice atom has KE < 1.0 eV.


ICISS directory
===============

This project shows how Impact Collision Ion Scattering Spectrometry
results can be simulated using a batch simulation process. The
example is discussed in the Simulation Primer (chapter 6).

Before you run the project, you MUST read the 'readme.txt' file which
is located in the \examples\iciss directory.

The example uses 2 keV He projectiles which are incident along a <112>
azimuth of the Cu(110) surface.

(The following remarks are only of interest if in future you want to
generate a similar target yourself using Spider.)
- To align this azimuth with the x-axis, I rotated a 'default' Cu(110)
  lattice by 35.26 degrees [arctan{1/sqrt(2)}].
- I also trimmed the lattice in the y-dimension, in the region
  y = -0.5 to +0.5.


MIXING directory
================

The system modelled here is 0.5 keV Ar-Cu(100).

This project is discussed in chapter 8 of the Simulation Primer. The
project is fairly generic, in that the output file can be used for a
variety of applications. The initial purpose of the project was to
examine recoil mixing in a bombarded target. Other information that
can be extracted from the output data are (a) projectile implantation
characteristics; (b) the "Wehner spot" pattern formed by ejected
particles.

NOTE: The output file from this project is about 24 MB in size.

The simulation uses a large (15x15x12 = 2700 atoms) target, and 225
incident projectile trajectories. The impact zone used is square in
shape, rather than the more correct triangular shape for normal
incidence on Cu(100). This does not lead to redundant calculations,
however, since vibrational effects are included in the simulation
(which removes strict surface symmetry).
