Hyperfine and spin–rotational structure of CaBr X 2Σ (v = 0) by molecular-beam laser-rf double resonance

The molecular-beam, laser–rf, double-resonance technique has been used to make high-precision measurements of the spin–rotation and hyperfine interactions in the X 2Σ (v = 0) electronic ground state of Ca79Br and Ca81Br. The spin–rotation interaction is found to have a strong N dependence. The Frosch–Foley magnetic hyperfine parameters b and c and the electric–quadrupole hfs parameter eqQ are determined for both molecules.