\begin{table}%T2
\caption{\label{tab2}Calculated and observed term energies (in Ryd) for \nifour. The second 
column shows the ab initio energies neglecting relativistic
effects (no relat.); the third column shows the energies including the effects
of mass, velocity, and Darwin
relativistic effects (1-B relat.) but without two-body interactions; the fourth  column gives the calculated
energies allowing for all relativistic effects (2-B rel.); and the fifth column gives the
experimental energies from NIST (\cite{NIST2000}).}
%\centering
\par
\begin{tabular}{lcccc}
            \hline\hline
 Level     &\multispan{3}{\ Present} & Experiment \\
           &No relat.&1-B rel.&2-B rel.& NIST (\cite{NIST2000})  \\
            \hline
$\rm 3d^7~^4F$&0.000000&0.000000&0.000000 &0.00000 \\
$\rm 3d^7~^4P$&0.167744&0.168143&0.167232 &0.15664 \\
$\rm 3d^7~^2G$&0.194507&0.194612&0.194259 &0.17473 \\
$\rm 3d^7~^2P$&0.213619&0.214542&0.215411 &0.20805 \\
$\rm 3d^7~^2H$&0.273222&0.273044&0.273261 &0.23661 \\
$\rm 3d^7~^2D$&0.244796&0.245531&0.248822 &0.24255 \\
$\rm 3d^7~^2F$&0.426665&0.427212&0.427617 &0.38753 \\
$\rm 3d^7~^2D$&0.642415&0.643563&0.645014 &0.60678 \\
$\rm 3d^64s~^6D$&1.050524&1.021174&1.021967 &1.00332 \\
$\rm 3d^64s~^4D$&1.174054&1.144630&1.145408 &1.09810 \\
$\rm 3d^64s~^4P$&1.329187&1.300472&1.301645 &1.26161 \\
$\rm 3d^64s~^4H$&1.323730&1.294378&1.293635 &1.26227 \\
$\rm 3d^64s~^4F$&1.348514&1.319496&1.319164 &1.27956 \\
$\rm 3d^64s~^4G$&1.385653&1.356394&1.357487 &1.31596 \\
$\rm 3d^64s~^2P$&1.401766&1.373031&1.375162 &1.31259 \\
$\rm 3d^64s~^2H$&1.396225&1.366841&1.367147 &1.32057 \\
$\rm 3d^64s~^2F$&1.422926&1.393841&1.393851 &1.33768 \\
$\rm 3d^64s~^2G$&1.458127&1.428833&1.430886 &1.37387 \\
$\rm 3d^64s~^4D$&1.471055&1.441942&1.442994 &1.38750 \\
$\rm 3d^64s~^2I$&1.474509&1.445083&1.445357 &1.40451 \\
$\rm 3d^64s~^2G$&1.490605&1.461311&1.464264 &1.41399 \\
$\rm 3d^64s~^2D$&1.546979&1.517824&1.517252 &1.44471 \\
$\rm 3d^64s~^2S$&1.554798&1.525544&1.528841 & \\
$\rm 3d^64s~^2D$&1.552943&1.524521&1.528960 &\\
$\rm 3d^64s~^2F$&1.647569&1.618736&1.619422 &1.55148 \\
$\rm 3d^64p~^6D^o$&1.612450&1.600081&1.599185&1.59328 \\
$\rm 3d^64s~^4F$&1.736458&1.707397&1.709217  &1.62704 \\
$\rm 3d^64p~^6F^o$&1.682306&1.669815&1.669569&1.64876 \\
$\rm 3d^64p~^6P^o$&1.709164&1.696714&1.696861&1.67615 \\
$\rm 3d^64p~^4D^o$&1.736066&1.723675&1.725165&1.68833 \\
$\rm 3d^64s~^2F$&1.812385&1.783258&1.784634&1.68428 \\
$\rm 3d^64p~^4F^o$&1.750378&1.737852&1.738949&1.69828 \\
$\rm 3d^64s~^4P$&1.734944&1.706121&1.707983 &\\
$\rm 3d^64p~^4P^o$&1.791677&1.779220&1.779713&1.73270 \\
$\rm 3d^64s~^2G$&1.843564&1.814675&1.816295  &1.72906 \\
$\rm 3d^64s~^2P$&1.812817&1.783908&1.786087  &\\
            \hline
         \end{tabular}
\end{table}