| Using density functional theory at B3LYP/LanL2DZ level, geometric structures and electronic properties of doped metal clusters were calculated. The optimizations were performed for copper doped aluminum (n=1-15) clusters and aluminum doped copper (n=1-12) clusters. Then, electron affinity, ionization potential, and Mulliken population analysis of doped atom Cu or Al, mean polarizability, polarizability anisotropy, dipole moments and highest occupied molecular orbital—lowest unoccupied molecular orbital (HOMO-LUMO) gaps are calculated. Results show that there is a magic number phenomenon in copper-doped aluminum clusters and the electronic characteristics depend strongly on the size of cluster. For n=13 cluster, the electron affinity and ionization potential changed more than 0.3 eV and 0.6 eV, respectively, compared with neighborhood clusters. Al13Cu is a magic cluster with a closed shell of 40 electrons as described by the jellium model. By the HOMOs analysis, the HOMO mostly consists of 3s and 3p of Al atom. Furthmore in the HOMO of Al6Cu and Al7Cu, the concentration of s-like and p-like electrons are very close, which are 33.8%,33.3% for Al6Cu and 44.2%,42.9% for Al7Cu. It can be predicted that the Al atom exhits two valences in these clusters, comparing with Al cluster. In the same way, our studies suggest that magic number configuration also occurs in aluminum doped Cun (n=1-11) clusters. The electronic properties of these clusters exhibit an odd/even alternation with increasing cluster size. The electron affinity of Cu5Al is small, while gap is higher than its neighbors, indicating that Cu5Al is more stable, as predicated by the jellium model. In (CuAl)n (n=1-7) calculation, CuAl is regarded as a unit, which contains 4 valence electrons. According to the jellium model, we can predict that (CuAl)2 and (CuAl)5 should be more stable than others clusters. This is confirmed by our results of (CuAl)5. Electronic properties of (CuAl)5 exhibit more change, except the mean polarizability, the ionization potential increases, electron affinity plays down, polarizability anisotropy decreases, and HOMO-LUMO gap increases up to maximum in this series of clusters.Adsorption energy of CH2 and CH3 radicals adsorbed on Cun (n=1-6) clusters were calculated. The optimizations of their geometric structures show that all stable structures of these clusters are in a two-dimensional (2D), without accounting of H atoms. Because certain potentials need to be overcome when these 2D-structures change, Cun (n=1-6) clusters generally keep these structures even when CH2 or CH3 radical is adsorbed. The calculations show that the adsorption of CH2 on Cun (n=1-6) is easier than that of CH3, and the adsorption energy of CH3 on the clusters exhibit odd/even alternation in which the energies with the odd number of Cu atom are larger than that with even number, suggesting easier adsorbing of CH3 with odd number of Cu atom clusters. The NPA analysis elucidate that the charge is transferred from the metal cluster to hydrocarbon, and with increasing n, the charge transferred is more. A frequency analysis indicates that with increasing n the variation of the several vibrational modes of C-H bonding is different, but they all approach to the vibrational frequency of CH2 and CH3 adsorbing on Cu metal surfaces; and there is a redshift in symmetry C-H stretching mode, the bigger the cluster, the more the redshift.Photoelectron spectra of AgmAun-(m+n=2-4) were calculated. In the generalized Koopman theorem (GKT), DOS (Density of States) is shifted by setting the HOMO energy as the negative vertical detachment energy (VDE), and in our works, the shifted is profermed by setting the electron affinity energies calculated as the vertical detachment energy. By comparing the calculated DOS with the photoelectron spectra reported, isomers with very small difference in energy can be distinguished, one can tell isomer from photoelectronic spectra and one can designate peaks in spectrum to the corresponding isomer.
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