  Using the general form of the Bethe-Salpeter wave functions for the bound
states consisting of two vector fields given in our previous work, we
investigate the molecular state composed of $D^{*+}_s$$D^{*-}_s$. However, for
the SU(3) symmetry the component $D^{*+}_s$$D^{*-}_s$ is coupled with the other
components $D^{*0}$$\bar{D}^{*0}$ and $D^{*+}$$D^{*-}$. Then we interpret the
internal structure of the observed \emph{Y}(4140) state as a mixed state of
pure molecule states $D^{*0}$$\bar{D}^{*0}$, $D^{*+}$$D^{*-}$ and
$D^{*+}_s$$D^{*-}_s$ with quantum numbers $J^P=0^+$. In this paper, the
operator product expansion is used to introduce the nonperturbative
contribution from the vacuum condensates into the interaction between two heavy
mesons. The calculated mass of \emph{Y}(4140) is consistent with the
experimental value, and we conclude that it is a more reasonable scenario to
explain the structure of Y (4140) as a mixture of pure molecule states.
