\begin{table}%t2
\caption{Experimental radiative lifetimes of two levels in Ir~I.}\label{irlifetimes}
%\centerline
{\begin{tabular}{lccccrlr}
\hline \hline\noalign{\smallskip}
Level$^a$ & Energy & $J$ & $\lambda_{\rm exc}^b$ & $\lambda_{\rm obs}^c$ &
\multicolumn{3}{c}{Lifetime (ns): Exp$^d$} \\ %&\multicolumn{1}{c}{Theory}\\
\cline{6-8}\noalign{\smallskip}
& (cm$^{-1}$)& & (\AA) & (\AA)   & \multicolumn{2}{c}{This work}  &
\multicolumn{1}{c}{G}  \\ %& \multicolumn{1}{c}{this work}       \\
\noalign{\smallskip} \hline \noalign{\smallskip}
5d$^{7}$6s($^{5}$F)6p z $^{6}{\rm F}_{11/2}$      & 28~452.32 & 5.5 & 3513.6 & 3902 &
320&\hspace{-4mm}(30) & 340(10)  \\ %& 101    \\
5d$^{7}$6s($^{5}$F)6p z $^{6}{\rm D}_{9/2}$       & 26~307.49 & 4.5 &        &      &
&\hspace{-4mm}     & 580(10)      \\ 
\hline 
\end{tabular}}
{$^a$ Level notation from \citet{Kleef57}.} \\
{$^b$ Laser wavelength used to populate the upper state.} \\
{$^c$ Wavelength used to detect the fluorescence signal.} \\
{$^d$ G = {Gough} et~al. (1983).}
\end{table}