deletions | additions       diff --git a/Photoemission.tex b/Photoemission.tex  index f6d902a..0f50cf4 100644  --- a/Photoemission.tex  +++ b/Photoemission.tex 
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evaluation of the total wavefunction in an extremely large portion of space (in principle a macroscopic one)   that would be impractical to represent in real space.   In Octopus we We have developed a scheme to calculate photoemission based on real-time TDDFT that is currently implemented in Octopus. We  use a mixed real and momentum space approach to solve the problem. Each Kohn-Sham orbital is propagated in real space on a restricted simulation box and then matched at the boundary with a momentum space representation on infinitely extended plane waves.   \begin{figure}[h!]  \begin{center}  \includegraphics[width=0.7\columnwidth]{figures//mask_scheme/mask_scheme.eps}  \caption{\label{fig:pes_sheme}  Scheme illustrating the mask method for the calculation of electron photoemission.  A mask function (a) is used to effectively split each Khon-Sham orbital into a bounded component   in $A$ and an unbounded one in $B$ according to the diagram in (b).}  \end{center}  \end{figure}  The matching is made with the help of a mask function $M(\vec{r})$, like the one shown   in Fig.~\ref{fig:pes_sheme}~(a), Fig.~\ref{fig:pes_sheme},  that separates each orbital into a bounded $\phi_i^A(\vec{r})$ and an unbounded component $\phi_i^B(\vec{r})$ as follows  \begin{equation}\label{eq:mask_split}  \phi_i(\vec{r},t) = M(\vec{r})\,\phi_i(\vec{r},t)+\left[1-M(\vec{r})\right]\phi_i(\vec{r},t)   =\phi_i^A(\vec{r},t)+\phi_i^B(\vec{r},t)\, .  \end{equation}  This property can be used to separate the spatial components during a time propagation   according to Fig.~\ref{fig:pes_sheme}~(b).  Starting from a set of orbitals localized in $A$ at $t=0$ it is possible to derive a   time propagation scheme with time step $\Delta t$ by recursively applying