A new approach to studying the luminescence spectra of free icosahedral and crystalline argon nanoclusters

• Published in: Low temperature physics (Woodbury, N.Y.) N.Y.), 2016-02, Vol.42 (2), p.156-159
• Main Authors: Doronin, Yu. S., Vakula, V. L., Kamarchuk, G. V., Tkachenko, A. A., Samovarov, V. N.
• Format: Article
• Language: English
• Subjects: Argon; Banded structure; Cathodoluminescence; Clusters; Crystal structure; Crystallinity; Excimers; Icosahedral phase; Luminescence; Nanoclusters
• ISSN: 1063-777X; 1090-6517
• DOI: 10.1063/1.4942580

We propose a new approach to analyzing the cathodoluminescence spectra of free argon nanoclusters, forming in a supersonic jet flowing into vacuum. Based on this approach, we conduct an analysis of the intensities of the luminescence bands of neutral and charged excimer complexes (Ar2)* and (Ar+ 4)*, measured for clusters with an average size ranging from 500 to 8900 atoms per cluster, and a diameter of 32–87 Å. It is shown that the concentration of the substance condensed into clusters, which determines the integrated intensity of the bands, is proportional to the logarithm of the average size of the clusters in the jet. An analysis of the normalized intensities of the (Ar2)* and (Ar+ 4)* bands for crystalline clusters with an fcc structure allowed us to establish that the luminescence of neutral (Ar2)* molecules comes from within the volume of the cluster, while the charged complexes (Ar+ 4)* emit from the subsurface layer. We highlighted an area of cluster dimensions at which the jet is dominated by quasi-crystalline clusters with an icosahedral structure, and it is shown that the transition from icosahedral clusters to fcc structures occurs when the average size of the cluster in the jet is N ¯ = (1000–1800) atoms/cluster.