\begin{table} 
\caption{Measured radiative lifetimes for ten \ion{Cr}{ii} levels in the 3d$^4$($^5$D)4p configuration. \label{t2}}  
%\centering
\begin{tabular}{cccccc} 
\hline \hline \noalign{\smallskip}
Term  & Energy 	& Observed 		& Exc. laser	& \multicolumn{2}{c}{Exp. lifetimes}\\ \cline{5-6} 
	 & 		         & fluorescence		& conversion	& Our work	& Prev. work\\
	 & (cm$^{-1}$) &  \lm$_{ \rm air}$ (\AA) & scheme$^a$	&  (ns)	& (ns)	\\
\hline                                                              	                        \noalign{\smallskip}                                                       	                    
$^4$F$_{3/2}$	& 51~485.15 & 3118.646 &	$2\omega$	&	4.2(4)		&						\\
$^4$F$_{5/2}$	& 51~669.48 & 3120.359 &	$2\omega$	&	4.1(4)		&                               		\\
$^4$F$_{7/2}$	& 51~788.88 & 3124.973 &	$2\omega$	&	4.1(3)		&                               		\\
$^4$F$_{9/2}$	& 51~942.70 & 3132.053 &	$2\omega$	&	4.1(3)		&                               		\\   
$^4$D$_{1/2}$	& 54~418.02 & 2873.806 &	$3\omega+S$	&	4.3(4)		&                               		\\
$^4$D$_{3/2}$	& 54~499.52 & 2867.089 &	$3\omega+S$	&	4.3(4)		&                               		\\
$^4$D$_{5/2}$	& 54~625.62 & 2870.432 &	$3\omega+S$	&	4.3(4)		&                               		\\
$^4$D$_{7/2}$	& 54~784.48 & 2875.987 &	$3\omega+S$  	&       4.3(4)		&     4.20(18)$^b$  \\              	                   
$^6$P$_{5/2}$	& 48~491.10 & 2762.589 &	$3\omega$	&	2.3(2)		& 2.45(8)$^b$, 2.5(1)$^c$, 2.4(2)$^d$ \\
$^6$P$_{7/2}$	& 48~632.12 & 2766.531 &	$3\omega$	&	2.4(2)		& 2.4(13)$^b$, 2.5(1)$^{c}$, 2.4(2)$^{d}$       \\
\hline
\end{tabular}
$^a$ $2 \omega$ -- frequency doubling, $3 \omega$ -- frequency tripling, $S$ -- Stoke shift.\\
$^b$ \citet{Pinnington93}.\\
$^c$ \citet{Schade90}.\\
$^d$ \citet{Bergeson93}.
\end{table}