Is there any easy way to add epigraphs to tables and graphs?

Question

I am a bit confused about how to add footnotes to tables. I have read some other similar questions but it is not working for me. I don't know what am doing wrong.

Here is a MWE:

\documentclass[12pt,twoside]{report}
\usepackage[headheight=18pt,a4paper, width=150mm, top=25mm, bottom=25mm, bindingoffset=6mm, headsep=18pt]{geometry}
\usepackage[spanish, es-noquoting]{babel}
%interprete de idioma castellano
\usepackage[utf8]{inputenc} %relacionado al input
\usepackage[T1]{fontenc} 
\usepackage{graphicx}
\usepackage{float}
\restylefloat{table}
\usepackage{threeparttable}
\usepackage{caption}

\begin{document}
\begin{threeparttable}[H]
\centering
\captionof{table}{Convergencia PM6-cluster}\label{table:convergencia_cluster_PM6}
\begin{tabular}{|l|l|l|}
\hline
\textbf{nºconf} & \textbf{$\Delta G^\circ_{SS}$} & \textbf{$\Delta G^\circ_{Packmol}$} \\ \hline
5 & -64.6 & -64.7 \\ \hline
10 & -65.5 & -64.1 \\ \hline
15 & -63.7 & -66.5 \\ \hline
180 & -66.6 & -66.4 \\ \hline
250 & -66.3 & -67.0 \\ \hline
\end{tabular}
\begin{tablenotes}
\item[a] En la tabla se compara $\Delta G^0$ de dos métodos de solvatación (SS y Packmol) con hamiltoniano PM6. Los valores de $\Delta G^0$ se dan en Kcal/mol. La sigla SS significa Solvateshell.
\end{tablenotes}
\end{threeparttable}
\end{document}


But it produces a footnote with too big letters. So maybe I am using it wrong.

edit

Answer 1

for legacy purpose:

You can use \footnotemark and \footnotetext for that. The latter outside of the threeparttable.

EDIT:

In threeparttable you have to specify the note's identifier with \tnote and use the identifier in the tablenotes-environment as optional argument to the \item. Note that the font size is not changed inside the tablenotes. For that you might issue a \footnotesize to reduce the font size. Also note, that you don't have to use the tablenotes environment nor the \tnote if you don't want to add footnote-like comments to your table, you can just put text there.

\documentclass[12pt,twoside]{report}
\usepackage[headheight=18pt,a4paper, width=150mm, top=25mm, bottom=25mm, bindingoffset=6mm, headsep=18pt]{geometry}
\usepackage[spanish, es-noquoting]{babel}
%interprete de idioma castellano
\usepackage[utf8]{inputenc} %relacionado al input
\usepackage[T1]{fontenc} 
\usepackage{threeparttable}
\usepackage{caption}

\begin{document}
\begin{threeparttable}
\centering
\captionof{table}{Convergencia PM6-cluster}\label{table:convergencia_cluster_PM6}
\begin{tabular}{|l|l|l|}
\hline
\textbf{nºconf} & \textbf{$\Delta G^\circ_{SS}$} & \textbf{$\Delta G^\circ_{Packmol}$} \\ \hline
5 & -64.6 & -64.7 \\ \hline
10 & -65.5 & -64.1 \\ \hline
15 & -63.7 & -66.5 \\ \hline
180 & -66.6 & -66.4 \\ \hline
250 & -66.3 & -67.0\tnote{a} \\ \hline
\end{tabular}
\footnotesize
\begin{tablenotes}
\item[a] En la tabla se compara $\Delta G^0$ de dos métodos de solvatación (SS y Packmol) con hamiltoniano PM6. Los valores de $\Delta G^0$ se dan en Kcal/mol. La sigla SS significa Solvateshell.
\end{tablenotes}
\end{threeparttable}

A second try without tablenotes:

\begin{threeparttable}
  \centering
  \captionof{table}{Foo}
  \begin{tabular}{ll}
    my & table\\
    being & nice
  \end{tabular}
  {\footnotesize Descriptive text}
\end{threeparttable}
\end{document}

Note that you don't even need threeparttable for this. You could as well use a regular table environment containing a tabular:

\documentclass[12pt,twoside]{report}
\usepackage[headheight=18pt,a4paper, width=150mm, top=25mm, bottom=25mm, bindingoffset=6mm, headsep=18pt]{geometry}
\usepackage[spanish, es-noquoting]{babel}
%interprete de idioma castellano
\usepackage[utf8]{inputenc} %relacionado al input
\usepackage[T1]{fontenc} 
\usepackage{caption}

\begin{document}
A third try without threeparttable:

\begin{table}
  \centering
  \caption{Foo}
  \begin{tabular}{ll}
    my & table\\
    being & nice
  \end{tabular}\\[0.5\baselineskip]
  \begin{minipage}{0.5\linewidth}
    \scriptsize
    long descriptive text. It is really long. Somebody should
    shorten it. Really, who reads all that stuff? Seems boring to me. You
    really should stop reading this.
  \end{minipage}

\end{table}
\end{document}