ROTATIONAL AND PAIRING PROPERTIES OF RB-74

We use a cranked shell model Monte Carlo (SMMC) approach to study rota tional properties and pair correlations in the odd-odd N = Z nucleus R b-74. The calculation is performed in the complete 1p-0f(5/2)-0g(9/2) model space with a residual interaction derived from the Paris potenti al, The calculated ground state is dominated by isovector J = 0 proton -neutron (pn) pairing. With increasing frequency the J = 0 pn correlat ions decrease to a constant value at around [J] = 3 +/- 1.5 (h) over b ar, while the isoscalar pn correlations (mainly J = 9) increase, Relat edly, the isospin decreases with frequency from its ground state value T = 1 as isoscalar correlations set in. This finding is in agreement with experiment, where at higher rotational frequency a T = 0 band bec omes energetically favored over the T = 1 ground state band. (C) 1997 Published by Elsevier Science B.V.