\begin{table}%[htdp]%t1 \par \caption{\label{default}Carbon dioxide: gas, pure solid, hydrate, and clathrate hydrate transitions.} %\centerline { $$ \begin{tabular}{l l l l l l} \hline\hline & Gas $\rm^{e}$ & Crystal $\rm^{a}$ & Hydrate $\rm^{b}$ & &Clathrate $\rm^{c}$\\ Assigned & & (4-21K) & (15K) & & (5.6K) \\ transitions & & CO$_2$ & H$_2$O/CO$_2=5$ & & Type I \\ &$\bar{\nu}$ (cm$^{-1}$) &$\bar{\nu}$ (cm$^{-1}$) &$\bar{\nu}$ (cm$^{-1}$) & &$\bar{\nu}$ (cm$^{-1}$)\\ \hline $\rm \nu_3(^{13}CO_2)$ &2283.488 &2282.6 &2278 &\multirow{2}{*}{\Large\{} &2271.3 \\ & & &2280.2 \\ $\rm \nu_3(^{18}OCO)$ &2332.113 &-- &-- &\multirow{2}{*}{\Large\{} &2319.5 \\ & & & & &\it{2330} \\ $\rm \nu_3$ $\rm^{d}$ &2349.143 &2343.1 &2341 &\multirow{2}{*}{\Large\{} &2335 \\ & & & & & 2347 \\ \hline First Fermi resonance & & & &&\\ \hline $\rm\nu_1+\nu_3\;_{FR2} (^{13}CO_2) ^{e}$ &3527.737 &3514 & & &\it{exp. at $\sim$3505} \\ $\rm\nu_1+\nu_3\; _{FR2} (^{18}OCO) ^{e}$ &3571.141 &3563 & & &\it{3550} \\ $\rm\nu_1+\nu_3\;_{FR2}$ &3612.842 &3599.1 &3592 &\multirow{2}{*}{\Large\{}&3589.7 \\ & & & & &3596 \\ $\rm\nu_1+\nu_3\;_{FR1} (^{13}CO_2) ^{e}$ &3632.911 &3632.4 & & &\it{3613} \\ $\rm\nu_1+\nu_3\;_{FR1} (^{18}OCO) ^{e}$ &3675.134 &3667.3 & & &\it{3651.9} \\ $\rm\nu_1+\nu_3\;_{FR1}$ &3714.783 &3708.0 &3702 &\multirow{2}{*}{\Large\{} &3692.7\\ & & & & & 3703.4\\ \hline First $\nu_3$ overtone & & & &&\\ \hline $\rm 2\nu_3$ & & &4678 & &-- \\ \hline Second Fermi resonance & & & &&\\ \hline $\rm 2\nu_1+\nu_3\;_{FR3}$ &4853.623 &4830.5 &4827 &\multirow{2}{*}{\Large\{}&4819.7 \\ & & & & &\it{4825.6} \\ $\rm 2\nu_1+\nu_3\;_{FR2}$ &4977.835 &4971.2 &4962 &\multirow{2}{*}{\Large\{}&4950.2 \\ & & & & &4962.2 \\ $\rm 2\nu_1+\nu_3\;_{FR1}$ &5099.660 &5086.6 &5083 &\multirow{2}{*}{\Large\{}&5066.2 \\ & & & & &\it{5075.3} \\ \hline \end{tabular}$$} \par \medskip $\rm^{a}$ Mid-infrared : pure CO$_2$ spectrum measured at 4~K in April 1996 with the same spectrometer; Near-infrared spectra at 21~K and assignments from Quirico \& Schmitt (\cite{Quirico1997}); $^{\rm b}$ from Bernstein et~al. (\cite{Bernstein2005}); $^{\rm c}$ position accuracy is estimated to better than 0.5~cm$^{-1}$, line positions in italics have higher uncertainties due to line blending, weakness, or saturation effects; $\rm^{d}$ clathrate antisymmetric stretching-mode assignments for the $\rm \nu_3(^{12}CO_2)$ based on Fleyfel \& Devlin (\cite{Fleyfel1991}); $^{\rm e}$ transitions are assigned based on Rothman (\cite{Rothman1986}). \end{table}