\begin{table}%T2
 \caption{\label{tab:dlines}Accurately known methanol transitions detected or potentially
   detectable in dark clouds, frequencies, lower state energies,
   line strengths, and laboratory and dark cloud references.}
 %\centerline
{
 \begin{tabular}{cllllll}
 \hline \hline   
\noalign{\smallskip}                               
Maser$^{a}$&Transition,~$J_k{=}^b$& Frequency (MHz)$^c$ &~$E_\ell^d$ (cm$^{-1}$) &~$S\mu^2$ (D$^2$)
& Laboratory ref.$^e$ & Dark cloud ref.$^f$\\
\noalign{\smallskip}                               
\hline 
\noalign{\smallskip}
I?&$1_{1}\to1_{1}A^{\mp}$&\d\d\d834.267(2)    &  11.705 & 1.2129 & Radford (1972) &\textit{Slysh et~al. (\cite{Slysh1995b}})\\
 &$2_{1}\to2_{1}A^{\mp}$ & \d\d2502.7785(10)  &  14.904 & 0.6725 & HD73         & ND \\
I?&$3_{1}\to3_{1}A^{\mp}$& \d\d5005.32079(20) &  19.703 & 0.4693 & HD73         &\textit{Kalenski{\u i} et~al. (\cite{Kalenski2004}})\\
II&$2_{0}\to3_{-1}E^f$   &  \d12~178.595(3)    &  13.556 & 1.9848 & Gaines et~al. (\cite{Gaines1974}) & Walmsley et~al. (\cite{Walmsley1988})\\
II&$2_{1}\to3_{0}E$      &  \d19~967.3961(2)   &  18.803 & 0.9224 & M~85 \\
I&$2_{2}\to2_{1}E$       &  \d24~934.382(5)    &  19.469 & 1.5948 & Gaines et~al. (\cite{Gaines1974})\\
I&$4_{-1}\to3_{0}E$      &  \d36~169.265(30)   &  18.803 & 2.5184 & T95 \\
&$1_{0}\to0_{0}A^+$      &  \d48~372.4558(7)   & \d0.000 & 0.8086 & HD73        & Friberg et~al. (\cite{Friberg1988})\\
&$1_{0}\to0_{0}E$        &  \d48~376.892(10)   & \d9.122 & 0.8084 & T95         & \textit{Kaifu et~al. (\cite{Kaifu2004}})\\
&$1_{0}\to2_{-1}E$       &  \d60~531.489(10)   & \d8.717 & 1.4742 & This work   & NO \\
&$1_{1}\to2_{0}E$        &  \d68~305.640(20)   &  13.963 & 0.4573 & This work \\
&$2_{1}\to1_{1}A^+$      &  \d95~914.309(5)    &  11.705 & 1.2141 & This work \\
&$2_{-1}\to1_{-1}E$      &  \d96~739.362(5)    & \d5.490 & 1.2133 & This work  & Friberg et~al. (\cite{Friberg1988})\\
&$2_{0}\to1_{0}A^+$      &  \d96~741.375(5)    & \d1.614 & 1.6171 & This work  & Friberg et~al. (\cite{Friberg1988})\\
&$2_{0}\to1_{0}E$        &  \d96~744.550(5)    &  10.736 & 1.6167 & This work  & Friberg et~al. (\cite{Friberg1988})\\
&$2_{1}\to1_{1}E$        &  \d96~755.511(5)    &  16.241 & 1.2443 & This work  & Menten et~al. (\cite{Menten1988})\\
&$2_{1}\to1_{1}A^-$      &  \d97~582.804(7)    &  11.733 & 1.2141 & This work \\
II&$3_{1}\to4_{0}A^+$    &   107~013.803(5)    &  16.134 & 3.0088 & This work \\
II&$0_{0}\to1_{-1}E$     &   108~893.963(7)    & \d5.490 & 0.9784 & This work   & Turner (\cite{Turner1998})\\
&$2_{2}\to1_{1}E$        &   121~689.975(10)   &  16.241 & 2.8297 & T95         \\
&$3_{1}\to2_{1}A^+$      &   143~865.801(10)   &  14.904 & 2.1584 & T95         \\
&$3_{0}\to2_{0}E$        &   145~093.707(10)   &  13.963 & 2.4249 & T95         \\
&$3_{-1}\to2_{-1}E$      &   145~097.370(10)   & \d8.717 & 2.1569 & T95         & Turner (\cite{Turner1998})\\
&$3_{0}\to2_{0}A^+$      &   145~103.152(10)   & \d4.840 & 2.4257 & T95         & Turner (\cite{Turner1998})\\
&$3_{1}\to2_{1}E$        &   145~131.855(10)   &  19.469 & 2.2119 & T95         \\
&$3_{1}\to2_{1}A^-$      &   146~368.342(50)   &  14.988 & 2.1585 & T95         \\
II&$2_{1}\to3_{0}A^+$    &   156~602.413(10)   & \d9.681 & 1.9963 & T95         \\
II&$1_{0}\to1_{-1}E$     &   157~270.851(10)   & \d5.490 & 1.4611 & T95         \\
II&$3_{0}\to3_{-1}E$     &   157~272.369(10)   &  13.556 & 3.3178 & T95         \\
II&$2_{0}\to2_{-1}E$     &   157~276.058(10)   & \d8.717 & 2.4090 & T95         \\
&$1_{1}\to1_{0}E$        &   165~050.195(10)   &  10.736 & 1.3466 & T95         \\
&$2_{1}\to2_{0}E$        &   165~061.156(10)   &  13.963 & 2.2373 & T95         \\
&$3_{1}\to3_{0}E$        &   165~099.271(10)   &  18.803 & 3.1170 & T95         \\
&$3_{2}\to2_{1}E$        &   170~060.581(10)   &  19.469 & 3.1205 & T95         & ND \\
&$4_{1}\to3_{1}A^+$      &   191~810.509(10)   &  19.703 & 3.0352 & T95         & ND \\
&$4_{0}\to3_{0}E$        &   193~415.367(10)   &  18.803 & 3.2327 & T95         & ND \\
&$4_{-1}\to3_{-1}E$      &   193~441.610(10)   &  13.556 & 3.0330 & T95         & ND \\
&$4_{0}\to3_{0}A^+$      &   193~454.361(10)   & \d9.681 & 3.2342 & T95         & ND \\
&$4_{1}\to3_{1}A^-$      &   195~146.760(10)   &  19.870 & 3.0353 & T95         & ND \\
\noalign{\smallskip} \hline
\end{tabular}}
\smallskip
For nomenclature see also notes to Table~\ref{tab:mlines}.
$^a$ I and~II mean that these lines are class~I and~II~maser
transitions, respectively, in some non-dark cloud regions (see Table~\ref{tab:mlines}).
$^f$ Only references reporting the first detection of a line in  cold
($T\approx 10$~K) dark clouds  are listed.
For non-dark cloud astronomical references to first detections,
see Lovas (2003).  "ND'' means that no astronomical
detection is reported in the latter reference; "NO'' means that
the line is not observable from the ground.
$^g$ This line appears in enhanced absorption (i.e. is over-cooled)
against the cosmological microwave background radiation.
References in italics report observations of a given
line that did not yield its detection.
\end{table}