\begin{table}%t1
\caption{\label{res}Rotational and hyperfine parameters of trans-HCOOH.}
\par
%\centering
$$
\begin{tabular}{lccr@{.}lcr@{.}lcr@{.}lccr@{.}lccr@{.}l}
\hline\hline \noalign{\smallskip}
Constant &&&     \multicolumn{8}{c}{This work}                                                                     &&& \multicolumn{2}{c}{Chardon et~al.}&&& \multicolumn{2}{c}{Winnewisser et~al.} 
\\
\cline{3-11}
\\[-3mm]
         &&& \multicolumn{2}{c}{Experiment\tablefootmark{a}}&&\multicolumn{2}{c}{Experiment\tablefootmark{b}}&&\multicolumn{2}{c}{Theory\tablefootmark{c}}&&& \multicolumn{2}{c}{(\cite{Chardon})}&&& \multicolumn{2}{c}{(\cite{Winne})}       \\
\hline
     $A_0$            & (MHz) &&  77~512&22444(68)   &&  77~512&22486(31)      &&\multicolumn{2}{c}{}&&&\multicolumn{2}{c}{}&&& 77~512&2354(11)      
     \\
     $B_0$            & (MHz) &&  12~055&104691(20)  &&  12~055&104683(10)     &&\multicolumn{2}{c}{}&&&\multicolumn{2}{c}{}&&& 12~055&10645(19)     
     \\
     $C_0$            & (MHz) &&  10~416&114012(20)  &&  10~416&1139857(96)    &&\multicolumn{2}{c}{}&&&\multicolumn{2}{c}{}&&& 10~416&11512(19)     
     \\
$\Delta_J$            & (kHz) &&      9&994322(44)  &&      9&994275(20)     &&\multicolumn{2}{c}{}&&&\multicolumn{2}{c}{}&&&     9&99603(23)    
 \\
$\Delta_{JK}$         & (kHz) &&    --86&22183(38)   &&    --86&22189(19)      &&\multicolumn{2}{c}{}&&&\multicolumn{2}{c}{}&&&   --86&2486(20)      
\\
$\Delta_K$            & (kHz) &&   1702&209(23)     &&   1702&2381(58)       &&\multicolumn{2}{c}{}&&&\multicolumn{2}{c}{}&&&  1702&447(15)       
\\
$\delta_J$            & (kHz) &&      1&948525(11)  &&      1&9485409(48)    &&\multicolumn{2}{c}{}&&&\multicolumn{2}{c}{}&&&     1&948815(32)    
\\
$\delta_K$            & (kHz) &&     42&7812(13)    &&     42&78384(53)      &&\multicolumn{2}{c}{}&&&\multicolumn{2}{c}{}&&&    42&7318(48)      
\\
  $\Phi_J$            & (Hz) &&      0&012733(33)  &&      0&012703(15)     &&\multicolumn{2}{c}{}&&&\multicolumn{2}{c}{}&&&     0&013143(97)    
  \\
$\Phi_{JK}$           & (Hz) &&      0&1319(25)    &&      0&13806(93)      &&\multicolumn{2}{c}{}&&&\multicolumn{2}{c}{}&&&     0&1021(60)      
\\
$\Phi_{KJ}$           & (Hz) &&    --10&6802(89)    &&    --10&7008(33)       &&\multicolumn{2}{c}{}&&&\multicolumn{2}{c}{}&&&   --10&565(23)       
\\
  $\Phi_K$            & (Hz) &&    120&19(23)      &&    120&464(37)        &&\multicolumn{2}{c}{}&&&\multicolumn{2}{c}{}&&&   121&195(76)       
  \\
  $\phi_J$            & (Hz) &&      0&005846(12)  &&      0&0058700(46)    &&\multicolumn{2}{c}{}&&&\multicolumn{2}{c}{}&&&     0&005763(11)    
  \\
  $\phi_{JK}$         & (Hz) &&      0&07970(74)   &&      0&08105(30)      &&\multicolumn{2}{c}{}&&&\multicolumn{2}{c}{}&&&     0&0975(32)      
  \\
  $\phi_K$            & (Hz) &&     15&74(13)      &&     16&087(49)        &&\multicolumn{2}{c}{}&&&\multicolumn{2}{c}{}&&&    14&82(22)        
  \\
        $L_J$         & (mHz) &&     --0&0000665(53) &&     --0&0000606(23)    &&\multicolumn{2}{c}{}&&&\multicolumn{2}{c}{}&&&    --0&0000719(93)   
        \\
     $L_{JJK}$        & (mHz) &&     --0&00213(10)   &&     --0&001981(49)     &&\multicolumn{2}{c}{}&&&\multicolumn{2}{c}{}&&& \multicolumn{2}{c}{}
     \\
     $L_{JK}$         & (mHz) &&     --0&03163(97)   &&     --0&03264(44)      &&\multicolumn{2}{c}{}&&&\multicolumn{2}{c}{}&&&    --0&0397(56)      
     \\
     $L_{KKJ}$        & (mHz) &&      1&0191(63)    &&      1&0198(32)       &&\multicolumn{2}{c}{}&&&\multicolumn{2}{c}{}&&&     0&875(34)       \\
        $L_K$         & (mHz) &&    --10&48(68)      &&    --11&077(64)        &&\multicolumn{2}{c}{}&&&\multicolumn{2}{c}{}&&&   --11&82(11)        
\\
        $l_J$         & (mHz) &&     --0&0000198(19) &&     --0&00002202(89)   &&\multicolumn{2}{c}{}&&&\multicolumn{2}{c}{}&&&     \multicolumn{1}{c}{}&    
\\
     $C_{aa}$(H(C))   & (kHz) &&     --6&835(90)     &&     --6&835(46)        &&    --7&02           &&&     --7&50(20)      \\
     $C_{bb}$(H(C))   & (kHz) &&      1&038(33)     &&      1&037(17)        &&     1&04           &&&     --7&2(40)       \\
     $C_{cc}$(H(C))   & (kHz) &&     --0&801(18)     &&     --0&8014(96)       &&    --0&82           &&&      7&5(40)       \\
     $C_{aa}$(H(O))   & (kHz) &&     --6&868(86)     &&     --6&868(45)        &&    --6&94           &&&     --6&55(20)       \\
     $C_{bb}$(H(O))   & (kHz) &&      0&781(38)     &&      0&781(20)        &&     0&77           &&&      8&2(40)       \\
     $C_{cc}$(H(O))   & (kHz) &&     --1&289(29)     &&     --1&290(15)        &&    --1&32           &&&     --8&6(40)       \\
1.5$D_{aa}$           & (kHz) &&      4&49(24)      &&      4&49(12)         &&     4&62           \\
($D_{bb}$-$D_{cc}$)/4 & (kHz) &&     --3&48(68)      &&     --3&53(35)         &&    --3&47           \\
 rms error\tablefootmark{d}        & (kHz) &&     1&08           &&       0&59          \\
\hline
\end{tabular}
$$
\tablefoot {\tablefoottext{a}{Transition frequencies from this work and from Chardon et~al. (\cite{Chardon}) included in the fit.}
\\
\tablefoottext{b}{Transition frequencies from this work, from Winnewisser et~al. (\cite{Winne}), and from Chardon et~al. (\cite{Chardon}) included in the~fit.}
\\
\tablefoottext{c}{Equilibrium value at the CCSD(T)/cc-pCV5Z level augmented by vibrational corrections obtained at the CCSD(T)/cc-pCVTZ level by means of the VPT2 approach.}
\\
\tablefoottext{d}{Standard deviation of the fit.}}
\end{table}