[BUG] Export of sub- and superscripts to LaTeX inconsistent in tables?

[Yu <yu_icq@gmx.at>]

Hello!

When I use superscripts/subscripts in tables, they are incorrectly
exported to LaTeX -- the placement of math-mode marks ($), braces ({,
}) seems mixed up.

As an example an excerpt of my current laboratory book.

========================
| Calculation         | Zn layers | E_tot [eV/atom] (new) |
(interpolated) | \Delta{}E_tot  [meV/atom] |
|---------------------+-----------+----------------------+----------------+-------------------|
[...]
The energy difference \Delta{}E_tot seems [...]
========================

This gets exported as:
========================
\begin{center}
\begin{tabular}{lllll}
 Calculation  &  Zn layers  &  E_tot [eV/atom] (new)  &  (interpolated)  &  \D\
elta\{}E_tot  [meV/atom]  \\
\hline
\end{tabular}
\end{center}


The energy difference $\Delta${}E$_{\mathrm{tot}}$ seems [\ldots{}]
========================

Outside the table it works as expected.

You can see 3 errors in the export of "\Delta{}E_tot" to latex in the table:
    1. There are no $ marks. During PDF-Conversion this causes
        "! Extra }, or forgotten $" messages.
    2. The braces around the subscript are missing -- only the first
character thus is
        recognized as a subscript by (pdf)latex.
    3. For some reason, the opening brace after Delta is escaped.

The problem doesn't depend on the specific case of a LaTeX entity
before the subscript (i.e. \Delta{}). It occurs too throughout the
document for combinations like "E_gb", though of course the escaped
brace  ( \{} ) doesn't occur there.

When explicitly writing "E_{tot}" in the table, this was exported as
"E_\{tot\}", which is just as unexpected.

I tested this with a freshly pulled version from the git repository
and with the org-mode sample above as the contents of a minimal file
with the same result.

king regards, Yu