Structural and vibrational determination of small gallium–arsenide clusters from CCSD(T) and DFT calculations

Relative stabilities of GanAsm (n + m ⩽ 4), as well as their structural and vibrational properties, were computed and analysed using a CCSD(T) reference method since experimental data in this area are sparse or unknown. The cc-pVTZ basis set is used for n + m = 3 while the cc-pVTZ-PP one is employed for n + m = 4. With the aim of investigating larger clusters, we explored several DFT functionals able to mimic the reliable CCSD(T) approach. Among them, the PBE0/SBKJC+sp,d is the most efficient, since average differences of about 0.042 Å and 5.1 cm−1 were obtained for bond lengths and fundamental vibrational frequencies, respectively. As further test, this model is used to investigate and revisit an experimental IR spectrum of GanAsm mixture previously published by Li et al. [S. Li, R.J. Van Zee, W. Weltner Jr., J. Chem. Phys. 97 (1993) 11393].