  Two photon decay widths of the $J^P = O^+$ scalar mesons $a_{0} (980)$,
$f_{0}(980)$, $f_{0}(1370)$ and $\chi_{c0}$ are calculated in a covariant model
which is characterized by the quark - antiquark structure. Previously such
models were used to calculate current form factors. Here a different
application is tried. A simple version of the model uses adjusted
nonrelativistic model parameters with small quark masses. The results seem to
prefer nonideal mixing of $f_0(980)$ and $f_0(1370)$. The calculated decay rate
of $\chi_{c0}$ agrees with the experimental results.
