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The CO adsorption on the In-doped SnO2 (1 1 0) surface has been studied by the first-principles calculations based on density functional theory. The study reveals that CO can be chemically adsorbed on the bridge site of the In-doped SnO2 (1 1 0) surface transforming into CO2. The favorable oxidization of CO on the surface occurs with a small reaction barrier of 1.03 eV and is exothermic by 1.72 eV. These results suggest that the In-doping can contribute to the improvement of gas sensing properties of the SnO2-based sensors for CO gas.

We present numerical results of ground-state energies of 9 molecules in the well-established G2 molecule set given by the Gutzwiller conjugate gradient minimization (GCGM) method. The method, beyond the commonly used Gutzwiller approximation, was recently developed based on Gutzwiller variational wave functions. We find that compared to benchmark data given by full configuration interaction, GCGM total energies are reasonably well reproduced with the minimum basis set. To include the dynamical correlation beyond the minimal basis calculations, we adopt the local density approximation for the dynamical correlation energy E c . By comparing the results with benchmark data given by experiments and large-basis configuration interaction, the GCGM total energies with E c are in general better reproduced, but discrepancies are still observed for some dimers.

The hydrated clusters of complexes formed by calcium ion and three different zwitterionic amino acids, glycine (Gly), threonine (Thr) and phenylalanine (Phe) have been studied in the gas phase at MP2/6-311++G(d,p), considering the coordination numbers 6–8 for Ca 2+ . The clusters with the first hydration shell around calcium ion exhibiting the 8-coordination configuration were found to be most preferred for all the three hydrated systems. The relative stabilities of Gly-, Thr- and Phe-Ca 2+ decrease in the order Thr-Ca 2+ (H 2 O) n > Phe-Ca 2+ (H 2 O) n > Gly-Ca 2+ (H 2 O) n upon hydration in contrast to the order without water Phe-Ca 2+ > Thr-Ca 2+ > Gly-Ca 2+ . It may demonstrate that the nature of side chain has remarkable influence on the stability of hydrated calcium–amino acid clusters. The NBO charges were analyzed to understand the bonding characteristics between the calcium ion and the amino acids. Spectroscopic characters of the most stable hydrated clusters can be assigned based on researching the calculated spectra.

The magnetic property and electronic properties such as ionization potentials and electron affinities of the Ni n ( n ⩽ 30) neutral and ionic clusters have been studied using the density functional theory calculations with the PBE exchange–correlation energy functional. The variations of the calculated magnetic and ionization potential behaviors of the neutral Ni n ( n ⩽ 30) clusters are in good agreement with the experimental data. The tendency of the calculated electron affinity is generally consistent with but has small deviations from the experimental results.

The carbon-rich structures of C9Sin (n = 1–5) clusters were studied by first-principles density functional calculations using the B3LYP hybrid exchange–correlation energy functional and 6-311++G(2df) basis set. By systematic investigation of the structures and energies, we found that in the structures of the carbon-rich clusters C9Sin (n = 1–5), the C atoms were found to form linear (n = 2), or single-ring (n = 1 and 3) or double-rings (n = 4 and 5) while the Si atoms prefer to attach to the carbon rings in the form of C2Si units. Based on the lowest-energy structures obtained from our calculations, the properties of the clusters such as binding energy, second difference in energy, HOMO–LUMO gap, adiabatic ionization potential (AIP), adiabatic electron affinity (AEA), vibrational frequency, bond orders and NBO charge transfer have been calculated and analyzed.