Stark Effect and Hyperfine Structure of Hydrogen Fluoride

The nuclear hyperfine structure constants and the electric dipole moment of hydrogen fluoride, H¹{F}¹⁹$, in the ground-vibration and first excited rotation state have been measured in a molecular beam electric resonance experiment. The hfs constants are: ${c}F=307.6±{}1.5$ kc/sec, ${c}ₚ={-}70.6±{}1.3$ kc/sec, $2/5{{g}ₚ{g}F{{{μ}}ₙₘ}²}{h〈{r}³〉}=57.6±{}0.44$ kc/sec. The apparatus was calibrated by observing Stark transitions in the ground-vibration and first excited rotation state of carbonyl sulfide, ${O}¹⁶C¹²{S}³²$, which gave ${{{μ}}HF}{{{μ}}OCS}=2.554±{}0.0037$, or ${{μ}}HF=1.8195±{}0.0026$ D, by using ${{μ}}OCS=0.7124±{}0.0002$ D. An absolute measurement of the OCS electric dipole moment gave ${{μ}}OCS=0.7120±{}0.003$ D. A digitally computed solution of the Stark effect with magnetic hyperfine structure was necessary to interpret the data. The theory and experiment are in good agreement over the range of electric-field strengths used in the experiment. The hfs constants are in excellent agreement with the averaged absolute values of these constants as measured in a molecular beam magnetic resonance experiment. The agreement has significance because of discrepancies between the results from the two resonance methods, for some other molecules, in previous experiments.