A semi-classical model for isoscalar giant resonances at finite temperatures

We present a study of the temperature dependence of the energies of isoscalar giant resonances with multipolarities L = 0, 2, 3 and 4, in the framework of the subtraction procedure of Bonche, Levit and Vautherin (BLV). The method is used to calculate, within a Thomas-Fermi (TF) model at finite temperatures, sum rules of the strength function in the random phase approximation (RPA). Special attention has been paid to the spurious contribution of the gas, which considerably alters the low-energy weighted sum rules, i.e. the low-energy part of the strength function; we find that when this spurious contribution is removed, the resonance energies show a weak dependence on temperature, up to the Coulomb instability onset. The temperature dependence of the nuclear incompressibilities in the scaling and in the constrained models have also been obtained.