The molecular beam electric resonance spectrum of OPF3

The molecular-beam electric resonance spectrum of phosphoryl fluoride (16OPF3) has been investigated. A hyperfine study of (K = 0) multiplets has been combined with earlier magnetic resonance data and chemical shift arguments to obtain four spin–rotation constants and two tensor spin–spin constants. The results (in kHz) are: [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text], dFF = −2.3(9), and dFF = 4.1(9). A study of molecular magnetic effects has yielded the two molecular g-factors [Formula: see text] and [Formula: see text] as well as the anisotropy in the susceptibility [Formula: see text]. The molecular quadrupole moment has been calculated. From a study of the Stark effect, the electric dipole moment has been determined for the ground vibrational state and for the (ν5 = 1) and (ν6 = 1) fundamentals. The results are: μ = 1.86847(10) D, (μ5 − μ)/μ = −3.49(4) × 10−3, and (μ6 − μ)/μ = −0.65(4) × 10−3. For each of these two excited vibrational states, the l-doubling constants qt, and DqJ(t) (t = 5,6) have been obtained. This work demonstrates that the molecular beam electric resonance method can be applied to symmetric tops with relatively large room temperature rotational partition functions by reducing the rotational temperature to a few degrees kelvin with the seeded beam technique.