Temperature concepts for small, isolated systems; 1/t decay and radiative cooling

We report on progress in our investigations of cluster cooling. The analysis of measurements is based on introduction of the microcanonical temperature and a statistical description of the decay of an ensemble with a broad distribution in temperature. The resulting time dependence of the decay rate is a power law close to t(-1), replaced by nearly exponential decay after a characteristic time for quenching by radiative cooling. We focus on results obtained for fullerene's, both anions and cations and recently also neutral C-60.