  We use \texttt{WDEC} to evolve grids of DAV star models adopting the element
diffusion scheme with pure and screened Coulomb potential effect. The core
compositions are thermonuclear burning results which are derived from
\texttt{MESA}. \texttt{MESA} yields composition profiles that the version of
WDEC used in this work could not accommodate (most notably the presence of
helium in the core of the model). According to the theory of rotational
splitting, Fu et al. identified 6 triplets for a DAV star HS 0507+0434B based
on 206\,h photometric data. The grids of DAV star models are used to fit the 6
reliable $m$ = 0 modes. When adopting the screened Coulomb potential, we obtain
a best fitting model of log($M_{\rm He}/M_{\rm *}$) = -3.0, log($M_{\rm
H}/M_{\rm *}$) = -6.1, $T_{\rm eff}$ = 11790\,K, $M_{\rm *}$ =
0.625\,$M_{\odot}$, log$g$ = 8.066, and $\sigma_{RMS}$ = 2.08\,s. Compared with
adopting the pure Coulomb potential, the value of $\sigma_{RMS}$ is improved by
34\%. The study may provide a new method for the research of mode trapping
properties.
