Stark hyperfine structure of hydrogen bromide

The ν=0, J=1,2 hyperfine spectra of hydrogen bromide have been measured with a molecular beam electric resonance spectrometer at electric fields of 1500–3500 V/cm. The hyperfine structure parameters were determined for H 79.81Br and D 79.81Br. The quadrupole interaction ratios are The distance derivative of the electric field gradient at the site of the bromine nucleus was determined to be d (q/qe)/d ([R−Re]/Re) =1.556(3). The magnetic octupole interaction of the bromine nucleus was negligible ‖ewΩ‖<0.5 Hz. The electric polarizability anisotropy was measured to be (α∥−α⊥) =0.37(9) Å3. The same technique was used for DCl with the result (α∥−α⊥) = 0.23(3) Å3. Numbers in parenthesis are uncertainties in the final figures.