\begin{table}
%\centering
\par
\caption{\label{SiC2-spec-parameters}Spectroscopic parameters\tablefootmark{a} (MHz) for SiC$_2$ obtained in the present investigation 
compared to a previous study.}
\begin{tabular}{lrr}
\hline \hline
Parameter & This work & He et~al. (2008)\\
\hline
$A-(B+C)/2$               &  40674.000~(81)    &  40674.191~(100)   \\
$(B+C)/2$                 &  11800.11932~(84)  &  11800.11861~(99)  \\
$(B-C)/4$                 &    678.41182~(76)  &    678.41301~(130) \\
$D_K$                     &   $-$1.3429~(185)  &   $-$1.2880~(227)  \\
$D_{JK}$                  &      1.624141~(59) &      1.624219~(88) \\
$D_J \times 10^3$         &   $-$1.1651~(80)   &   $-$1.1845~(115)  \\
$d_1 \times 10^3$         &   $-$2.4371~(53)   &   $-$2.4392~(111)  \\
$d_2 \times 10^3$         &   $-$7.1766~(30)   &   $-$7.2002~(80)   \\
$H_{KJ} \times 10^6$      &    669.68~(104)    &    670.39~(151)    \\
$H_{JK} \times 10^6$      & $-$138.26~(12)     & $-$138.66~(39)     \\
$H_J \times 10^6$         &      0.9810~(187)  &      1.0079~(201)  \\
$h_1 \times 10^9$         & $-$193.0~(101)     & $-$180.2~(247)     \\
$h_2 \times 10^9$         & $-$578.1~(84)      & $-$513.3~(301)     \\
$h_3 \times 10^9$         &    185.8~(67)      &    157.0~(93)      \\
$L_{KKJ} \times 10^9$     & $-$135.4~(69)      & $-$138.5~(80)      \\
$L_{JK} \times 10^9$      &    14.68~(175)     &    14.34~(266)     \\
$L_{JJK} \times 10^9$     &  $-$12.11~(28)     &  $-$11.06~(78)     \\
$L_J \times 10^{12}$      &    138.9~(166)     &       $-$           \\
$P_{KKKJ} \times 10^{12}$ &     20.\tablefootmark{b}         &     20.\tablefootmark{b}         \\
\hline
\end{tabular}
\tablefoot {\tablefoottext{a}{Watson's $S$-reduction was used in the representation $I^r$. 
Numbers in parentheses are 1~$\sigma$ uncertainties in units of the 
least significant figures.}
\tablefoottext{b}{Kept fixed to estimated value.}}
\end{table}