+\chapter{Modifications to the VASP code}
+\label{app:patch_vasp}
+
+\section{Description}
+The modifications to the VASP code allow to rotate all atom coordinates individually in the particle position evaluation routine of VASP.
+In that way constraints for every atom can be applied independently of the chosen basis.
+A patch against version 4.6 of the VASP code containing these modifications is available for download\footnote{http://www.physik.uni-augsburg.de/\~{}zirkelfr/download/posic/sd\_rot\_all-atoms.patch}.
+
+\section{Usage}
+
+Since this feature only makes sense in selective dynamics mode, it can be switched on by adding the word {\em Transformed} in front of the {\em selective dynamics} switch.
+This feature only works in direct mode.
+Two values of angles need to be added after the extra flags of each atom.
+The first angle corresponds to the rotation of the basis about the $z$-axis.
+The second angle determines the rotation about the transformed $x$-axis, $x'$.
+All values have to be supplied in degrees.
+All these information is given in the POSCAR file as can be seen in the follwing example:
+\begin{verbatim}
+cubic diamond
+ 5.48000000000000
+ 2.9909698580839312 0.0039546630279804 -0.0039658085666586
+ 0.0039548953566878 2.9909698596656376 -0.0039660323646892
+ -0.0039680658132861 -0.0039674231313905 2.9909994291263242
+ 216 1
+Transformed selective dynamics
+Direct
+ 0.994174 0.994174 -0.000408732 T F T 45 36.5145
+ 0.182792 0.182792 0.981597 T F T -135 -5.95043
+ ...
+ 0.119896 0.119896 0.0385525 T F T -135 21.8036
+\end{verbatim}
+In case of the first atom the basis is transformed by a rotation of $45^{\circ}$ and $36.5145^{\circ}$ about the $z$ and $x'$ axis.
+Relaxation of this atom is constrained to the $y''$-axis.
+