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diff --git a/thesis/thesis.tex b/thesis/thesis.tex
index 599d5605..01c0a766 100644
--- a/thesis/thesis.tex
+++ b/thesis/thesis.tex
@@ -119,33 +119,70 @@
 \section{Overview of Theory}
 Summarise the literature, refer to past research etc
 
-\subsection{Electron structure of surface}
+\subsection{Electron Spectra of a Surface}
 \begin{itemize}
-	\item Overview of electron spectrum properties
+	\item Description of the near surface region
 	\begin{itemize}
-		\item Density of states $n(E)$
-		\item Energy band structure $E(\vect{k})$
-	\end{itemize}
-	\item Properties of surface region
-	\begin{itemize}
-		\item Difference between potential of surface and bulk
+		\item All real solids occupy finite volumes in space.
+		\item The surface of a solid is important because interactions between the solid and its surroundings occur in the near surface region.
+		\item Characterised physically by:
 		\begin{itemize}
-			\item Change between the two limits in the ``near-surface'' region
+			\item Termination of periodic crystal lattice
+			\item Violation of geometric order
+			\item Distortion of interatomic distances and hence interaction forces
+			\item There is a transition ``near surface'' region between bulk and surface properties, roughly 5 atomic distances. 
 		\end{itemize}
-		\item Theoretical models for the potential, 1D vs 3D
+		\item Potential seen by an electron at a surface can differ greatly from the bulk
+		\item $\implies$ the electron spectra of the near surface region differs from the bulk spectra
+		\item Simplest case: Step potential at surface
 		\begin{itemize}
-			\item Simplest case is a step potential.
-			\item Various improvements on this model, discussed in Komolov's book.
+			\item Metal & Semiconductor
+		\end{itemize}
+		\item In reality, 
+		
+	\end{itemize}
+
+	\item The Electron Spectra
+	\begin{itemize}
+		\item Electron Spectra describes the energy eigenstates for an electron in a Bulk or Surface potential
+		\item Characterised by 
+		\begin{enumerate}
+			\item Energy dispersion $E(\vect{k})$
 			\begin{itemize}
-				\item Possibly adapt CQM project to model these potentials, if I get time
+				\item Dependence of Energy on electron wave vector
+				\item Obtained theoretically by solving Scrhrodinger's Equation
+				\item For a free electron gas, $E = \frac{\hbar^2 k^2}{2m}
+				\item Periodic potential in bulk solid leads to band gap structure of $E(\vect{k})$
+				\item Periodic potential $\implies$ E is periodic. Only needs to be defined in first Brillouin zone.
 			\end{itemize}
-		\end{itemize}
-		\item Limitations of theoretical models
-		\begin{itemize}
-			\item Real surface is not a step potential
-			\item Adsorption of foreign particles onto the surface also plays a large role in determining the electron spectrum.
-		\end{itemize}
+			\item Density of States $N(E)$
+			\begin{itemize}
+				\item $N(E) = \frac{\Delta N}{\Delta E} = \frac{1}{4\pi^3}\int_S\left(\der{E}{k}\right)^{-1} dS$
+				\item Integral is in momentum space over the isoenergetic surface of energy $E$
+				\item For a free electron gas, $N(E) = $
+			\end{itemize}
+		\end{enumerate}
 	\end{itemize}
+
+	\item Surface states
+	\begin{itemize}
+		\begin{enumerate}
+			\item Tamm States: Periodic potential in solid, free space outside, jump at surface
+			\begin{itemize}
+				\item Energy eigenvalues lie in the forbidden band of the bulk spectra
+				\item Attenuation of eigenvalues from surface to vacuum, oscillation of state within surface
+				\item Max electron density occurs on the crystal surface
+			\end{itemize}
+			\item Shockley states: Potential of surface and bulk cells equal
+			\begin{itemize}
+				\item Corresond to free valences (dangling bonds) at the surface
+			\end{itemize}
+		\end{enumerate}
+		\item Tamm and Shockley states arise from two extreme models (large change and small change respectively between bulk and surface). In reality, a combination of Tamm and Shockley states appear.
+		\item These states arise from termination of the lattice; but the surface cells are assumed undistorted
+		\item In reality surface cells are distorted by relaxation and reconstruction of the surface
+	\end{itemize}
+
 	\item Main reference: Komolov "Total Current Spectroscopy"
 	\item "Solid State Physics" textbooks and "Electron Spectroscopy" textbooks 
 \end{itemize}
@@ -213,7 +250,10 @@ I really think I should actually find plasmonic effects before writing too much
 
 \subsection{Total Current Spectroscopy}
 \begin{itemize}
-	\item Overview of technique
+	\item 
+	\item Total Current Spectroscopy methods measure the total current of secondary electrons as a function of primary electron energy.
+	\item These methods are distinguished from ``differential'' methods (such as Auger electron spectroscopy and energy loss spectroscopy) which measure the secondary electron spectrum at a fixed primary electron energy.
+	\item 
 	\begin{itemize}
 		\item Low energy beam of electrons incident on sample
 		\item Measure slope of resulting I-V curve