\begin{table}%t3
%\centering
\par
\caption{\label{tab:products}Wavenumbers (in \cm) of the photoproducts that appeared after UV irradiation of pyridine, pyrimidine or s-triazine. The band assignments were taken from {\it a} \citet{milligan}; {\it b} \citet{ruiterkamp}; {\it c} \citet{satoshi}; and {\it d} \citet{stroh}. The bands for HCN and C$_2$H$_2$ in the pyrimidine photoproducts are shifted with respect to the bands given in the references, so a complex between HCN and C$_2$H$_2$ is inferred (see text).}
$$
\begin{tabular}{lr@{.}ll}
	\hline\hline
	Irradiation & \multicolumn{2}{c}{Wavenumber} & Band assignment \\
	time        & \multicolumn{2}{c}{(\cm)}     & \\
	\hline
	\textbf{pyridine} & \multicolumn{3}{c}{} \\
	 10 min&	 904&1 & [HAr$_2$]$^+$ $^a$ \\
	\hline
	\textbf{pyrimidine} & \multicolumn{3}{c}{} \\
	 10 min&  904&1 & [HAr$_2$]$^+$ $^a$ \\
	                  & 3297&8 & C$_2$H$_2$ $^b$ (complexed with HCN)\\
	                  & 3314&7 & HCN $^c$ (complexed with C$_2$H$_2$) \\
	\hline
	\textbf{s-triazine} & \multicolumn{3}{c}{} \\
	 10 s	& 3288&6 & --  \\
				           & 3264&0 & c-(HCN)$_3$ C-H stretch $^c$ \\
				           & 2098&5 & c-(HCN)$_3$ C-N stretch $^c$ \\
				           &  763&7 & c-(HCN)$_3$ in-plane bend $^c$ \\
				           &  732&9 & c-(HCN)$_3$ out-of-plane bend $^c$ \\
		           1 min	& 3288&6 & --  \\
				           & 3275&6 & --  \\
				           & 3264&0 & c-(HCN)$_3$ C-H stretch $^c$ \\
				           & 3258&2 & --  \\
				           & 2098&5 & c-(HCN)$_3$ C-N stretch $^c$ \\
				           &  763&7 & c-(HCN)$_3$ in-plane bend $^c$ \\
			     	      &  732&9 & c-(HCN)$_3$ out-of-plane bend $^c$ \\
	           10 min& 3249&1 & --  \\
				           & 2295&8 & CNCN pseudo-symm. stretch $^d$ \\
				           & 2054&2 & CNCN pseudo-asymm. stretch $^d$ \\
				           &  904&1 & [HAr$_2$]$^+$ $^a$ \\
	\hline
	\end{tabular}
$$
\end{table}