Thermal radiation of laser heated niobium clusters Nb(+)(N), 8 ⩽ N ⩽ 22.

The thermal radiation from small, laser heated, positively charged niobium clusters has been measured. The emitted power was determined by the quenching effect on the metastable decay, employing two different experimental protocols. The radiative power decreases slightly with cluster size and shows no strong size-to-size variations. The magnitude is 40-50 keV/s at the timescale of several microseconds, which is the measured crossover time from evaporative to radiative cooling.