From cc1859e9a25b7c2a54e66515a6bb45ce918d28c1 Mon Sep 17 00:00:00 2001
From: Blaise Thompson <blaise@untzag.com>
Date: Sun, 12 Nov 2017 13:47:12 -0600
Subject: public

---
 public.tex | 116 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++---
 1 file changed, 112 insertions(+), 4 deletions(-)

(limited to 'public.tex')

diff --git a/public.tex b/public.tex
index 89cc6af..9c859e7 100644
--- a/public.tex
+++ b/public.tex
@@ -1,12 +1,120 @@
 % http://scifun.chem.wisc.edu/Thesis_Awards/chapter_guidelines.html
 
-\chapter{Public}  % -------------------------------------------------------------------------------
+\chapter{Public}
 
+\section{Chemical systems}  % ---------------------------------------------------------------------
 
-\section{Why spectroscopy?}
+Chemical systems are complex!  %
+They contain many molecules ($10^{25}$ in a cup of coffee, 1 trillion in each human cell).  %
+These molecules have multiple interaction modes, both internal (intramolecular) and external
+(intermolecular).  %
+The reactivity of the system taken as a whole can be dominated by very rare but very important
+species, \textit{e.g.} catalysts.  %
 
+Despite this complexity, scientists have gotten very good at describing chemical systems through
+representations of dynamic equilibrium.  %
+In such situations, several key parameters emerge:  %
+\begin{itemize}
+  \item concentration
+  \item timescale (rate)
+  \item lengthscale
+\end{itemize}
 
-\section{CMDS in practice}  % ---------------------------------------------------------------------
+\subsection{Concentration}
 
+\subsection{Timescale}
 
-\subsection{Ultrafast light sources}
\ No newline at end of file
+% TODO: dynamics in chemical systems: collision time, dephasing, rotation, relaxation, diffusion...
+
+\subsection{Lengthscale}
+
+\section{Analytical chemistry}  % -----------------------------------------------------------------
+
+Traditionally, chemists have seen fit to divide themselves into four specializations: analytical,
+inorganic, organic, and physical.  %
+In recent years, materials chemistry and chemical biology have become specializations in their own
+right.  %
+This dissertation focuses on analytical chemistry.  %
+
+Analytical chemists separate, identify, and quantify chemical systems.  %
+To do this, we build instruments that exploit physical properties of the chemical components:  %
+\begin{itemize}
+  \item separation science (chromatography, electrophoresis)
+  \item mass spectrometry
+  \item electrochemistry
+  \item microscopy
+  \item spectroscopy
+\end{itemize}
+Spectroscopy is a family of strategies that exploit the interaction of chemical systems with
+light.  %
+
+\section{Spectroscopy}  % -------------------------------------------------------------------------
+
+Molecules respond to electric fields.  %
+Static electric fields cause charged molecules (ions) to move, as in electrophoresis and mass
+spectrometry.  %
+Oscillating electric fields, also known as light, can interact directly with the molecules
+themselves, driving transitions.  %
+However, these transitions can only be driven with the appropriate frequency of light
+(resonance).  %
+Different frequencies (colors) of light interact with different kinds of transitions, revealing
+different features of the molecule of interest.  %
+
+% TODO: different energy ranges / transition types (nuclear, rotational, vibrational, electronic)
+
+% TODO: how is a photon created or absorbed?
+
+\subsection{Nonlinear spectroscopy}
+
+Spectroscopy is fantastic, but sometimes simple experiments don't reveal everything.  %
+Nonlinear spectroscopy uses multiple electric fields simultaniously, revealing even more
+information about the chemical system.  %
+
+% TODO: simple graphic of homogeneous vs inhomogeneous broadening
+
+% TODO: 2D freq-freq with increasing inhomogeneity (from Dan's theory work)
+
+\section{Instrumentation}  % ----------------------------------------------------------------------
+
+To accomplish nonlinear spectroscopy, specialized light sources are needed:  %
+\begin{itemize}
+  \item gigantic electric fields
+  \item ultrafast time resoution
+  \item tunable frequencies
+\end{itemize}
+
+\subsection{LASER}
+
+These sources are made using Light Amplified by the Stimulated Emission of Radiation (LASER).  %
+
+% TODO: discussion of the original LASER, basic LASER physics
+
+% TODO: discuss temporal coherence
+
+% TODO: discuss pulsed sources
+
+By keeping a wide range ofr colors in phase simulatniously, we are able to create truly ultrafast
+pulses of light.  %
+The work presented in this dissertation was primarily taken using a 35 fs 1 KHz system.  %
+
+35 fs ($35\times10^{15}$ second) pulses are incredibly short:
+\begin{equation}
+  \frac{\text{pulse duration (35 fs)}}{\text{time between pulses (1 ms)}} \approx
+  \frac{\text{5.75 months}}{\text{age of universe (13.7 billion years)}}  % TODO: cite age
+\end{equation}
+proportionally, our sample spends 6 months in the ``sun'' for every age of the unverse in the
+dark.  %
+
+Because all of the energy within the pulse is compressed to such a short period of time, these
+pulses are also incredibly powerful:
+\begin{equation}
+  \frac{\text{energy per pulse (4 mJ)}}{\text{pulse duration (35 fs)}} \approx
+  \frac{\text{US electricity generation} (5.43\times10^{11} W)}{5}  % TODO: cite generation
+\end{equation}
+this laser outputs electric fields one fifth as powerful as total US electricity generation (2016).
+
+% TODO: pulses are very thin (draw circle, use thickness of paper) to motivate 'hard to handle'
+
+\subsection{OPA}
+
+% https://osf.io/vwhjk/
\ No newline at end of file
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