An electron electric dipole moment search in theX³Δ₁ground state of tungsten carbide molecules

We identify the X 3Δ1 electronic ground state of tungsten carbide (WC) as a candidate molecular system in which to search for a permanent electric dipole moment (EDM) of the electron. The valence electrons in tungsten carbide experience an effective electric field of order 54 GV cm−1 when the molecule is placed in a laboratory electric field of just a few mV cm−1. Currently, a continuous tungsten carbide molecular beam is under construction. Tungsten atoms are evaporated from a resistively heated tungsten filament and are entrained in a noble gas jet containing a small fraction of methane. Tungsten carbide molecules are formed through the reaction W + CH4 → WC + 2H2.