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The present review article focuses on the impact of the Jahn-Teller effect (JTE) including hidden JTE and pseudo JTE on the ground and low-lying electronic structures of small transition, main group, and mixed metal clusters. The discussions are based on the results acquired from the quantum chemical analysis involving complete active space multiconfiguration self-consistent field (CASMCSCF or CASSCF) together with multireference singles and doubles configuration interaction (MRSDCI) theories. Related computational results from density functional (DFT) and coupled cluster (CC) theories, and the available experimental evidences on the JT-distorted structures are also included for comparative analysis. The role of the relativistic effects on several heavy metal clusters is discussed in detail, since these effects could lead to either enhancement or the quenching of the JTE. The final section of the review manifests the JT-distortion of several mixed metal clusters of icosahedral symmetry and they are explained through a much simpler shell structure (jellium) model. [ABSTRACT FROM AUTHOR]

Electronic structures of neutral lead–silicon clusters of up to six atoms are determined by global optimization of the potential energy hyper surface using Metropolis Monte Carlo and genetic algorithm (GA) methods followed by a bond strength propensity model, and by local optimization using density functional theory at the B3LYP/aug-cc-pVTZ-pp level. For each cluster, geometries of those stable isomers whose relative energies are within 1.0 eV are reported. Average binding energy per atom, band gap, ionization potential (IP), electron affinity (EA), and vertical detachment energy of the most stable isomer of each type of cluster are computed to study their dependences on the size of the cluster. Polarizability, chemical potential, hardness and electrophilicity index of the most stable isomers are estimated to study their relative stabilities and chemical reactivities. Relative strengths of metal–metal interactions are determined from a study of all one-step fragmentation processes. IR intensities and Raman activities for all the vibrational modes of the most stable isomers are calculated. [ABSTRACT FROM AUTHOR]