Adsorption of CO on pure and mixed clusters of tin and germanium up to five atoms: A theoretical study

► Geometries of the most stable CO complexes of small tin-germanium clusters are optimized. ► Kinetic and thermodynamic stabilities of these cluster-CO complexes are studied. ► Variations of the adsorption energy, HOMO-LUMO energy gap, NBO charge on CO fragment, etc. are reported. ► Correlations among C-O bond length, C-O stretching frequency, CO binding energy, etc. are established.