  In the framework of the one boson exchange model, we have calculated the
effective potentials between two heavy mesons $B \bar{B}^{*}$ and $D
\bar{D}^{*}$ from the t- and u-channel $\pi$, $\eta$, $\rho$, $\omega$ and
$\sigma$ meson exchange with four kinds of quantum number: $I=0$,
$J^{PC}=1^{++}$; $I=0$, $J^{PC}=1^{+-}$; $I=1$, $J^{PC}=1^{++}$; $I=1$,
$J^{PC}=1^{+-}$. We keep the recoil corrections to the $B \bar{B}^{*}$ and $D
\bar{D}^{*}$ system up to $O(\frac{1}{M^2})$. The spin orbit force appears at
$O(\frac{1}{M})$, which turns out to be important for the very loosely bound
molecular states. Our numerical results show that the momentum-related
corrections are unfavorable to the formation of the molecular states in the
$I=0$, $J^{PC}=1^{++}$ and $I=1$, $J^{PC}=1^{+-}$ channels in the $D
\bar{D}^{*}$ systems.
