\begin{table}%t1
%\centering
\par
\caption {\label{tab_opacsource}Scattering and absorption processes involving H and 
He~nuclei, considered in this work.} 
\begin{tabular}{llll}
\hline
\hline
Process  & Symbol & Reaction & References and Comments \\
\hline
\multirow{3}*{\it Rayleigh} & $\sigma_{\rm Ray}$($\HH_2$) & $\HH_2 + h\nu
\rightarrow \HH_2 + h\nu'$ & Dalgarno \& Williams (\cite{Dalgarno62}) \\\cline{4-4}
& $\sigma_{\rm Ray}$($\HH$) & $\HH + h\nu \rightarrow \HH + h\nu'$&
\multirow{2}*{Dalgarno (\cite{Dalgarno62})}\\
& $\sigma_{\rm Ray}$($\He$) & $\He + h\nu \rightarrow \He + h\nu'$& \\
\hline
{\it Thomson} & Th($\e$) &$\e + h\nu \rightarrow \e + h\nu'$ & NIST
(2006 CODATA recommended value)\\
\multirow{8}*{\it free-free} & $\sigma_{\rm ff}$($\HH^-$) & 
$\HH+\e +h\nu \rightarrow \HH + \e$& John (\cite{John88}) \\
& \multirow{1}*{$\sigma_{\rm ff}$($\HH$)} & 
\multirow{1}*{$\HH^+ + \e + h\nu \rightarrow \HH^+ + \e $} & Method as in Kurucz (\cite{Kurucz70}) based on  Karsas \& Latter (1961)\\
&$\sigma_{\rm ff}$($\HH_2^+$) & $\HH^+ + \HH + h\nu \rightarrow \HH^+ + \HH$ & Lebedev et~al. (\cite{Lebedev03})\\
&$\sigma_{\rm ff}$($\HH_2^-$) & $ \HH_2 + \e +h\nu \rightarrow \HH_2 + \e$ & John (\cite{John75})\\
&$\sigma_{\rm ff}$($\HH_3$) & $\HH_3^+ + \e + h\nu \rightarrow \HH_3^+ + \e $& $\sigma_{\rm ff}(\HH_3)=\sigma_{\rm ff}(\HH)$ (assumed) \\
&$\sigma_{\rm ff}$($\He^-$) & $\He + \e + h\nu \rightarrow \He+ \e$ & Carbon et~al. (\cite{Carbon69}) \\
&$\sigma_{\rm ff}$($\He$) &$\He^+ + \e + h\nu \rightarrow \He^+ + \e$& $\sigma_{\rm ff}(\He)=\sigma_{\rm ff}(\HH)$ (assumed)\\
&$\sigma_{\rm ff}$($\He^+$) &$\He^{++} + \e + h\nu \rightarrow \He^{++} + \e$ & $\sigma_{\rm ff}(\He^+)=\sigma_{\rm ff}(\HH)$ (assumed)\\
\hline
\multirow{7}*{\it bound-free} & $\sigma_{\rm bf}$($\HH^-$) & $\HH^- + h\nu \rightarrow \HH + \e$ & John (1998) \\\cline{4-4}
&  \multirow{2}*{$\sigma_{\rm bf}$($\HH$)} & \multirow{2}*{$\HH + h\nu \rightarrow \HH^+ + \e$} & Method as in Kurucz (\cite{Kurucz70}) based on\\
& & & Gingerich (\cite{Gingerich69}) and Karsas \& Latter (1991)\\\cline{4-4}
 & $\sigma_{\rm bf}$($\HH_2^+$) & $\HH_2^+ + h\nu \rightarrow \HH^+ + \HH $ & Lebedev et~al. (\cite{Lebedev03})\\\cline{4-4}
&\multirow{2}*{$\sigma_{\rm bf}$($\He$)} &  \multirow{2}*{$\He + h\nu \rightarrow \He^+ + \e$} & Method as in Kurucz (\cite{Kurucz70}) based on\\
& & & Gingerigh (1964) and Hunger \& Van Blerkom (\cite{Hunger67}) \\\cline{4-4}
& $\sigma_{\rm bf}$($\He^+$) & $\He^+ + h\nu \rightarrow \He^{++} + \e$ &  Hunger \& Van Blerkom (\cite{Hunger67})\\
\hline
\multirow{1}*{\it bound-bound} & $\sigma_{\rm bb}$($\HH$) & \multirow{1}*{$\HH + h\nu \rightarrow \HH^*$}& Kurucz (\cite{Kurucz70}) including Stark broadening\\
\multirow{6}{2cm}{\it Collision\\induced\\absorption} & \multirow{2}*{$\sigma_{\rm CIA}$($\HH_2/\HH_2$)} & \multirow{2}*{$\HH_2+\HH_2+h\nu \rightarrow \HH_2+\HH_2$} & $600\K<T<7000 \K$,  $20\cm^{-1}<\tilde{\nu}<20~000\cm^{-1}$ \\
& & & Borisow et~al. (1997) \\\cline{4-4}
 & \multirow{2}*{$\sigma_{\rm CIA}$($\HH_2/\He$)} & \multirow{2}*{$\HH_2+\He+h\nu \rightarrow \HH_2+\He$} & $1000\K<T<7000\K$, $25\cm^{-1}y<\tilde{\nu}<20~088\cm^{-1}$ \\
& & & J\o rgensen et~al. (\cite{Jorgensen00})\\\cline{4-4}
& \multirow{2}*{$\sigma_{\rm CIA}$($\HH/\He$)} & \multirow{2}*{$\HH+\He+h\nu \rightarrow \HH+\He$} & $1500\K <T<10~000 \K$, $50\cm^{-1}<\tilde{\nu}<1~1000\cm^{-1}$\\
& & &  Borisow et~al. (2001) \\
\hline
\end{tabular}
\vspace*{4mm}
\end{table}