\begin{table}%t4
\caption{\label{table:ni_iso}Ni~\textsc{i} isotopes used and scaled $\log gf$ values.} 
%\centerline
 {\begin{tabular}{c r c c} 
\hline \hline
\noalign{\smallskip}
Ni isotope & \%${}^{{a}}$ & Wavelength [nm]${}^{{b}}$ & $\log gf$ \\
\hline 
\noalign{\smallskip}
   ${}^{58}$Ni    & 68.27  & 630.0335  & --2.2757 \\ 
   ${}^{60}$Ni    & 26.10  & 630.0355  & --2.6933 \\ 
   ${}^{61}$Ni    &  1.13  & 630.0365  & --4.0569 \\ 
   ${}^{62}$Ni    &  3.59  & 630.0375  & --3.5549 \\ 
   ${}^{64}$Ni    &  0.91  & 630.0395  & --4.1509 \\ 
\hline
\end{tabular} }
\par
\smallskip
   $^{ {a}}$  Isotopic fractions from \citet{Rosman1998}.
   $^{ {b}}$   Wavelength of main component and isotopic splitting from \citet{Johansson2003}.
\end{table}