Structural, energetic and response electric properties of cyclic selenium clusters: an ab initio and density functional theory study

• Published in: Theoretical chemistry accounts 2012-06, Vol.131 (6), Article 1239
• Main Author: Alparone, Andrea
• Format: Article
• Language: English
• Subjects: Atomic/Molecular Structure and Spectra; Chemistry; Chemistry and Materials Science; Inorganic Chemistry; Organic Chemistry; Physical Chemistry; Regular Article; Theoretical and Computational Chemistry
• ISSN: 1432-881X; 1432-2234
• DOI: 10.1007/s00214-012-1239-2

The geometries, relative stabilities, binding energies, second-order difference of total energy (Δ 2 E ), vertical ionization energies (VIEs), vertical electron affinities (VEAs) and dipole polarizabilities of neutral Se 2 and cyclic Se n ( n  = 3–12) clusters have been systematically investigated using conventional ab initio [HF, MP2, MP3, MP4, CCSD, CCSD(T)] and density functional theory (B3LYP, CAM-B3LYP) levels with the Dunning’s correlation-consistent (cc-pVDZ, aug-cc-pVDZ, d-aug-cc-pVDZ and aug-cc-pVTZ) and Sadlej (POL and POL-DK) basis sets. For each cluster size, various structural isomers have been considered and optimized to search for the lowest-energy structure. The effects of the geometry, basis set and theoretical level on the calculated properties have been discussed. The relative stability of the clusters has been analyzed using binding energy per atom, Δ 2 E and VIE–VEA gap. The computed binding energies and VIEs have been compared with the available observed data. The calculated properties show a strong dependence upon the size and geometry of the cluster. The even-numbered Se n with n  = 6 and 8 are predicted to be relatively stable clusters. The physico-chemical properties of selenium clusters have been compared to those of the sulphur homologues. On passing from sulphur to selenium clusters the binding energy per atom decreases, whereas the mean dipole polarizability per atom increases.