\begin{table}%t1
\caption{\label{tab:grain}Parameters for the interaction of hydrogen
and deuterium atoms with dust grains of different 
compositions and surface morphologies.}
%\centerline
 {\small \begin{tabular}{lllll}
\hline\hline
\noalign{\smallskip}
& Amorphous carbon &   Olivine  &  Amorphous silicate & Low density ice   \\
Parameter & Katz (1999) &  Katz (1999) &  Perets (2007) & Perets (2005) \\
\noalign{\smallskip}
\hline
\noalign{\smallskip}
$\rho$ (g \ccm)  &  2.16 &  $3^a$  & 3.5 & 0.94\\
$s$ (\scm) & $5(13)$ &  $2(14)$ & $7(14)$ & 5(13)$^a$\\
$d$ ($\AA$)  &  14.14 &  7.07  & 3.78 &  14.14$^a$\\
$E_{\rm H}^{\rm des}$ (meV)  &  56.7 &  32.1 & 44.0 & 52.3 \\[3mm]
$E_{\rm D}^{\rm des}$ (meV)  &  61.7 &  37.1 & 49.0 & 57.3 \\[3mm]
$E^{\rm diff}_{\rm I}$ (meV)  &  44.0 &  24.7 & 35.0 & 44.5\\
$\nu_{\rm I}$ & $10^{12}$ & $10^{12}$ & $10^{12}$ & $10^{12}$ \\
\hline
\end{tabular}}
\medskip
$^{a}$ Assumed sensible values, as they are not given in the cited papers.
%\vspace*{2.5mm}
\end{table}