Concentration gradient model

This model abandons the concept of layers for linear concentration gradients, although a layer structure can still be simulated by a judicious choice of parameters. The linear gradient segments may also be sequenced to simulate other profile shapes. A little cunning is required to make optimum use of this model while limiting the number of variable parameters to only three.

The total signal intensity arising from this depth profile will be the sum of the intensity arising from each linear gradient segment :

eq1

The contribution of each linear gradient segment to the total intesity can be calculated as represented below :

<img src="images/gradient.jpg" alt='eq15' width="675" height="560" class='centre'/>

In general, for j segment junctions (inflection points in the profile) :

eq15

Various ways of exploiting this algorithm are coded into the stand-alone software "ARXPSolver" and in later versions of "arxps.zip" in the downloads section.