GROWTH-PATTERN OF ZIRCONIUM CARBON CLUSTERS - FURTHER EVIDENCE FOR FORMATION OF MULTICAGE STRUCTURES

A time-of-flight mass spectrometer coupled with a laser vaporization source is utilized to study the intensity distributions of metal-carbon clusters, namely, Zr(m)C(n) and Ta(m)C(n). Two distinct cluster growth patterns are observed under the present experimental conditions, i.e. Zr(m)C(n) building through a metal:carbon ratio of 2:3 while Ta(m)C(n) through a 1:1 ratio. These different growth patterns lead to two completely different cluster distributions, observed magic numbers, and cluster structures. The Ta(m)C(n) clusters can be well accounted for by the formation of face-centered cubic (fcc) structures. Importantly, both the growth pattern and the magic numbers in the Zr(m)C(n) clusters are rigorously consistent with expectations for the formation of multicage structures.