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**by M. Lepers, R. Vexiau, M. Aymar, N. Bouloufa and O. Dulieu**

**Using the multipolar expansion, we compute the long-range interactions between two identical polar bialkali molecules in their rovibronic ground level. In the absence of external electric field, their van der Waals interaction is characterized by huge van der Waals coefficients, more than three order of magnitude larger than those for alkali atoms. When applying an external electric field this huge isotropic van der Waals interaction is shown to compete with the expected anisotropic dipole-dipole interaction. For critical values of the electric field magnitude and intermolecular distances our calculations predict the mutual orientation of the two molecules but with no preferential direction in the lab frame. The strongly correlated nature of the corresponding eigenstates opens new possibilities to study many-body quantum physics.**

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