\begin{table}%t3
%\begin{center}
\par
\caption{Spectroscopic parameters$^a$ (MHz) of monodeuterated methyl 
cyanide, CH$_2$DCN and dimensionless weighted standard deviation wrms.}
\label{parameter_1D}
% \smallskip
$$
\begin{tabular}[t]{lr@{}l}
\hline \hline
Parameter & \multicolumn{2}{c}{Value} \\
\hline
$A$                      & 121~074&.677~(20)       \\
$B$                      &   8~759&.197~94~(23)   \\
$C$                      &   8~608&.542~55~(24)   \\
$D_K$                    &        1&.97              \\
$D_{JK} \times 10^3$     &      143&.336~1~(138)   \\
$D_J \times 10^3$        &        3&.469~982~(137) \\
$d_1 \times 10^6$        &    $-$79&.164~(46)       \\
$d_2 \times 10^6$        &     $-$4&.776~(35)       \\
$H_K \times 10^6$        &      100&.                \\
$H_{KJ} \times 10^6$     &        1&.688~(192)      \\
$H_{JK} \times 10^9$     &      837&.5~(49)         \\
$H_J \times 10^{12}$     &      400&.4~(191)        \\
$h_1 \times 10^{12}$     &      149&.0~(84)         \\
$L_{KKJ} \times 10^9$    &    $-$10&.82~(68)        \\
$L_{JK} \times 10^{12}$  &       58&.~(28)          \\
$L_{JJK} \times 10^{12}$ &     $-$5&.37~(55)        \\
wrms                     &        0&.740             \\
\hline
\end{tabular}
$$
%\end{center}
\par
$^a$ Watson's $S$ reduction has been used in the representation $I^r$. 
Numbers in parentheses are one standard deviation in units of the least 
significant figures. Parameters without quoted uncertainties have been 
estimated; see Sect.~\ref{a_and_d}.%\\
\end{table}