Hyperfine Structure Constants of HF and DF

Abstract
The radio frequency spectrum of HF and DF is measured by the molecular‐beam electric resonance method. The measurements are in the lowest vibrational state (υ = 0) and first rotational state (J = 1) . The constants obtained are: HFDFμ (D)1.826526 (7)1.818805 (5)CF (kHz)307.637 (20)158.356 (45)CH (kHz)− 71.128 (24)− 5.755 (19)SHF (kHz)28.675 (5)4.434 (9)JHF (kHz)0.529 (23)(eqQ) D354.238 (78) The electron coupled spin–spin interaction, JHF = + 530 Hz .