\begin{table}%t4
\caption {\label{products}Potential photoproducts with infrared transitions.}             % title of 
%\centerline
 {\begin{tabular}{l c c c c c }        % centered columns (4 columns)
\hline\hline
Species & Band & Band position & Fitting region &$\sigma$ band area & Band strength$^{a}$\\
& & (cm$^{-1}$)& (cm$^{-1}$)& (cm$^{-1}$)& (cm$^{-1}$)\\
\hline                 % inserts double horizontal lines2135.2489
H$_2$O & $\nu_2$ & 1670 & 1600--1670 & ul$^{b}$ & $1.2\times10^{-17}$ (1)\\
CH$_3$ &$\nu_2$ & 1385 & 1380--1390 & ul & $6.9\times10^{-19}$ (2)\\
CH$_4$ & $\nu_4$ & 1301 & 1290--1310 & 0.002 & $1.2\times10^{-17}$ (3)\\
CO & $\nu_1$ & 2135 & 2125--2145 & 0.001 & $1.1\times10^{-17}$ (1)\\
HCO & $\nu_1$ & 1850 & 1840--1860 & 0.0005 & $2.1\times10^{-17}$ (2)\\
H$_2$CO & $\nu_2$ & 1245 & 1228--1265 & 0.01 & $1.0\times10^{-18}$ (4)\\
CH$_2$OH & $\nu_4$ & 1195 & 1185--1195 & 0.01 & $1.6\times10^{-17}$ (2)\\
C$_2$H$_6$ & $\nu_{12}$ & 822 & 809--832 & 0.001 & $1.6\times10^{-17}$ (5)\\
CO$_2$ & $\nu_1$ & 2340 & 2330--2350 & 0.005 & $1.2\times10^{-17}$ (1)\\
CH$_3$CHO & $\nu_7$ & 1350 & 1337--1350 & 0.003 & $6.1\times10^{-18}$ (5)\\
CH$_3$CH$_2$OH & $\nu_{12}$ & 1380 & 1380--1395 & 0.002 & $1.9\times10^{-18}$ (5)\\
HCOOH & $\nu_3$ & 1740 & 1739--1773 & ul & $6.7\times10^{-17}$ (6)\\
CH$_3$OCH$_3$& $\nu_{10}$ & 1161 & 1151--1171 & 0.003 & 1.2$\times10^{-17}$ (7)\\
HCOOCH$_3$& $\nu_9$ & 1214 & 1216--1233 & ul & $2.1\times10^{-17}$ (2)\\
HOCH$_2$CHO& $\nu_{6}$ & 861 & 851--871 & ul & $3.4\times10^{-18}$ (8)\\
CH$_3$COOH& $\nu_{14}$ & 1746/1770 & 1760--1772 & ul & $1.1\times10^{-16}$ (9)\\
(CH$_2$OH)$_2$& $\nu_{14}$ & 866/890 & 851--876 & 0.006 & $3.4\times10^{-18}$ (8)\\
X-CHO/X-COOH$^{c}$& CO stretch & 1680--1780 & -- & 0.01 & $5.4\times10^{-17}$ (2, 6, 8)\\
\hline
\end{tabular}}
\par
\smallskip
$^{a}$ The listed values are transmission band strengths, for our RAIRS experiments they are scaled by a factor of~5.5, determined empirically. \\
$^{b}$ Only an upper limit could be determined. \\
$^{c}$ An average of the HCOOH, HCOOCH$_3$ and HOCH$_2$CHO band strengths of~6.7, 4.8 and $4.6\times10^{-17}$~cm$^{-1}$ is used.\\
(1) \citet{Gerakines95}, (2) calculated band strengths from \citet{Bennet07a},   (3) \citet{dHendecourt86},  (4) \citet{Schutte93},  (5) \citet{Moore98},  (6) \citet{Hudson99},  (7) from CH$_3$OH:CH$_3$OCH$_3$ ice mixture spectroscopy,  (8) \citet{Hudson05}, (9) \citet{Marechal87}.
\end{table}