Experimental Results and Discussion

Abstract

Optical properties of clusters have been exploited already for more than one and a half millenia before clusters have been identified as special entities and cluster science been established as an own field of research. As a matter of fact, ancient technologists eagerly produced clusters in glass from empirical recipes (of course not knowning the microscopic structure and processes) because of their beautiful and splendid colors whose brilliance fascinated people. It is not surprising that in particular the purple color of Au and Cu clusters, having been difficult to produce and, hence, rare, were regarded as the emperors color. One of the probably unsurpassed treasures of the antiquity concerning color beauty is a Roman goblet of the fourth century, now to be seen in the British Museum in London, which shows the Greek saga of Lykurgos. Its fame is due to the shining colors generated by a composition of Ag and Au clusters [4.1].