Magnetoelectrostatic Trapping of Ground State OH Molecules

We report magnetic confinement of neutral, ground state OH at a density of ∼3×10³  cm^-3 and temperature of ∼30  mK. An adjustable electric field sufficiently large to polarize the OH is superimposed on the trap in various geometries, making an overall potential arising from both Zeeman and Stark effects. An effective molecular Hamiltonian is constructed, with Monte Carlo simulations accurately modeling the observed single-molecule dynamics in various trap configurations. Magnetic trapping of cold polar molecules under adjustable electric fields may enable study of low energy dipolar interactions.