\begin{table}%t2
\par
\caption{\label{tab:sup_exps}Pure ice spectroscopy and TPD experiments.}                   %\centerline
 {\small \begin{tabular}{l c c c c}
\hline\hline
Species & Formula&Mass (amu) &Thick.$^{a}$ (ML) &$E_{\rm des}^{a}$ (K)\\
\hline                 % inserts double horizontal lines
Ethane &C$_2$H$_6$ &30 &5 [3] &2300 [300]\\
Methanol &CH$_3$OH &32 &25 [10] & 4700 [500]\\
Acetaldehyde &CH$_3$CHO  &44 &4 [2] &3800 [400]\\
Dimethyl ether &CH$_3$OCH$_3$  &46 &$\sim$4 & 3300 [400]\\
Ethanol &CH$_3$CH$_2$OH  &46 &5 [2]&5200 [500]\\
Formic acid &HCOOH  &46& 5 [2] &5000 [500]\\
Methyl formate &HCOOCH$_3$ &60 &3 [1] & 4000 [400]\\
Acetic acid &CH$_3$COOH &60 &3 [1] &6300 [700]\\
Glycolaldehyde &HOCH$_2$CHO &60 &3 [1] &5900 [600]\\
Ethylene glycol &(CH$_2$OH)$_2$ &62 &7 [3] & 7500 [800]\\
\hline
\end{tabular}}
\par
\smallskip
$^{a}$ Values in brackets indicate uncertainties.\\
\end{table}