  The DAV star R808 was observed by 13 different telescopes for more than 170
hours in April 2008 on the WET run XCOV26. 25 independent pulsation frequencies
were identified by this data set. We assumed 19 $m$ = 0 modes and performed an
asteroseismological study on those 19 modes. We evolve grids of DAV star models
by \texttt{WDEC} adopting the element diffusion scheme with pure and screened
Coulomb potential effect. The core compositions are from white dwarf models
evolved by \texttt{MESA}, which are thermal nuclear burning results. Our best
fitting model is from the screened Coulomb potential scenario, which has
parameters of log($M_{\rm He}/M_{\rm *}$) = -2.4, log($M_{\rm H}/M_{\rm *}$) =
-5.2, $T_{\rm eff}$ = 11100\,K, $M_{\rm *}$ = 0.710\,$M_{\odot}$, log$g$ =
8.194, and $\sigma_{RMS}$ = 2.86\,s. The value of $\sigma_{RMS}$ is the
smallest among the four existing asteroseismological work. The average period
spacing is 46.299\,s for $l$ = 1 modes and 25.647\,s for $l$ = 2 modes. The
other 6 observed modes can be fitted by $m$ $\neq$ 0 components of some modes
for our best fitting model. Fitting the 25 observed modes, we obtain a
$\sigma_{RMS}$ value of 2.59\,s. Considering the period spacings, we also
assume, that at least in one case, we detect an $l$ = 2 trapped mode.
