Studies on the cluster growth dynamics of vanadium-oxide and titanium-oxide clusters and on the structure and stability of zirconium-oxide clusters.
Abstract
Cluster growth dynamics of the V_nOm and Ti_pOq clusters produced by the laser ablation/supersonic expansion technique has been studied by covariance mapping time-of-flight mass spectrometry. Two different distribution components have been observed in the V_nO_m^+ and Ti_pO_q^+ mass spectra. The less fluctuating V_2O3 and Ti_2O3 are "nuclei" for the oxygen rich component Or. The more fluctuating V_2O and Ti_2O2 are "nuclei" for the oxygen poor component Op. Larger clusters grow from these "nuclei" by very specific pathways which involve only the uptake of VO or VO_2, and TiO_2, respectively. The formation processes of these "nuclei" will be discussed in some detail. The stability and structures of the Zr_nOm clusters have been studied by mass spectrometry and density functional theory calculations. The high signal intensity of the Zr_5O_10^+ ion is due to the high stability of the (ZrO_2)5 neutral cluster. Density functional theory calculations show that the most stable isomer structures of (ZrO_2)5 have compact geometries. The few structures most likely present at temperatures under 3000 K will be discussed.
- Publication:
-
APS March Meeting Abstracts
- Pub Date:
- March 2000
- Bibcode:
- 2000APS..MARR16002F