  With 78.7 days of observations for PG 0112+104, a pulsating DB star, from
Campaign 8 of $Kepler$ 2 mission, Hermes et al. made a detailed mode
identification. A reliable mode identification, with 5 $l$ = 1 modes, 3 $l$ = 2
modes, and 3 $l$ = 1 or 2 modes, was identified. Grids of DBV star models are
evolved by \texttt{WDEC} with element diffusion effect of pure Coulomb
potential and screened Coulomb potential. Fitting the identified modes of PG
0112+104 by the calculated ones, we studied the difference of element diffusion
effect between adopting pure Coulomb potential and screened Coulomb potential.
Our aim is to reduce the fitting error by studying new input physics. The
starting models including their chemical composition profile are from white
dwarf models evolved by \texttt{MESA}. They were calculated following the
stellar evolution from the main sequence to the start of the white dwarf
cooling sequences. The optimal parameters are basically consistent with that of
previous spectroscopic and asteroseismological studies. The pure and screened
Coulomb potential lead to different composition profiles of the C/O-He
interface area. High $k$ modes are very sensitive to the area. However, most of
the observed modes for PG 0112+104 are low $k$ modes. The $\sigma_{RMS}$ taking
the screened Coulomb potential is reduced by 4\% compared with taking the pure
Coulomb potential when fitting the identified low $k$ modes of PG 0112+104.
Fitting the $Kepler$ 2 data with our models improved the $\sigma_{RMS}$ of the
fit by 27\%.
