OH hyperfine ground state: From precision measurement to molecular qubits

We perform precision microwave spectroscopy--aided by Stark deceleration--to reveal the low-magnetic-field behavior of OH in its {sup 2}{pi}{sub 3/2} rovibronic ground state, identifying two field-insensitive hyperfine transitions suitable as qubits and determining a differential Lande g factor of 1.267(5)x10{sup -3} between opposite-parity components of the {lambda} doublet. The data are successfully modeled with an effective hyperfine Zeeman Hamiltonian, which we use to make a tenfold improvement of the magnetically sensitive, astrophysically important {delta}F={+-}1 satellite-line frequencies, yielding 1 720 529 887(10) Hz and 1 612 230 825(15) Hz.