Eur. Phys. J. D 32, 329-337 (2005)
https://doi.org/10.1140/epjd/e2005-00026-8

A density functional study of small Al_xO_y (x,y = 1-4) clusters and their thermodynamic properties

Zentrum für Astronomie und Astrophysik, Technische Universität Berlin, Hardenbergstr. 36, 10623 Berlin, Germany

Corresponding author: ^a patzer@astro.physik.tu-berlin.de

Received: 17 May 2004
Revised: 7 July 2004
Published online: 15 February 2005

Abstract

We report thermodynamic properties of small aluminium oxide clusters of mixed stoichiometric ratio Al_xO_y . The rigid rotator-harmonic oscillator approximation is used to calculate the partition function as it is generally applied in thermodynamic studies of polyatomic molecules. The molecular data used to set up the partition functions were computed by density functional techniques employing the BP86 gradient corrected exchange correlation functional. Thereby, the results of three species viz. AlO₄, Al₄O₂, and Al₄O₃ previously not reported in the literature are included in this study. Equilibrium geometric parameters, energies, selected harmonic vibrational wave numbers of energetically low–lying stationary points are presented along with corresponding absorption coefficients. The resulting thermodynamic functions of aluminium oxides are consistent with the JANAF thermochemical data compilation. These functions are used to determine the temperature dependent chemical equilibrium partial pressure distributions for different aluminium to oxygen ratios.