Assessing the validity of theoretical results

We present recent theoretical results for the V3 and Au4 clusters. Calculations of the V3 doublet system indicate that the 6-311+G(d) basis set is sufficiently flexible to provide reliable minimum energy structures and vibrational frequencies, that these structures and frequencies are insensitive to spin contamination of the wave function when the BPW91 functional is used, and that changing to the B3LYP functional may result in very different structures and frequencies. A computationally less expensive scalar relativistic treatment of Au4 clusters gives structural properties that are in good agreement with those obtained using a four-component method. PACS. 31.15.Ew Density-functional theory – 31.30.Jv Relativistic and quantum electrodynamic effects in atoms and molecules – 36.40.Mr Spectroscopy and geometrical structure of clusters