Rotational and pairing properties of 74Rb

We use a cranked shell model Monte Carlo (SMMC) approach to study rotational properties and pair correlationsin the odd-odd N = Z nucleus 74Rb. The calculation is performed in the complete 1p-0ƒ52-0g92 model space with a residual interaction derived from the Paris potential. The calculated ground state is dominated by isovector J = 0 proton-neutron (pn) pairing. With increasing frequency the J = 0 pn correlations decrease to a constant value at around 〈J〉 = 3 ± 1.5h̷ while the isoscalar pn correlations (mainly J = 9) increase. Relatedly, the isospin decreases with frequency from its ground state value T = 1 as isoscalar correlations set in. This finding is in agreement with experiement, where at higher rotational frequency a T = 0 band becomes energetically favored over the T = 1 ground state band.