[Tex/LaTex] How to add custom space in table of contents

Question

How can I add extra space between two specfied sections in the TOC?

i.e. I want to add space only at the arrow:

Is this even possible in a simple way?

Here's a minimal example:

\documentclass{article}
\makeatother
\begin{document}
\tableofcontents

\section{Sec 1}
\section{Sec 2} % I want space between section 2 and 3 in the table of contents
\section{Sec 3}
\section{Sec 4}
\section{Sec 5}

\end{document}

(I am also using the classicthesis template if that makes a difference)

Thanks in advance.

Answer 1

In this case, I used the optional argument of \section, to make the toc entry have a blank line stacked under it. The only thing you need to pay attention to is that if the entry is long enough to wrap in the toc, just stack under the last word of the entry, rather than under the whole entry.

\documentclass{article}
\usepackage{stackengine}
\begin{document}
\def\stacktype{L}
\tableofcontents

\section{Sec 1}
\section[\stackunder{Sec 2}{}]{Sec 2} % I want space between section 2 and 3 in the table of contents
\section{Sec 3}
\section{Sec 4}
\section{Sec 5}

\end{document}