The structures and electronic states of zinc–water clusters Zn_n(H₂O)_m(n = 1–32 and m = 1–3)

Abstract

Ab initio and Density Functional Theory (DFT) calculations have been carried out for zinc-water clusters Zn(n)-(H2O)(m) (n = 1-32 and m = 1-3, where n and m are the numbers of zinc atoms and water molecules, respectively) to elucidate the structure and electronic states of the clusters and the interaction of zinc cluster with water molecules. The binding energies of H2O to zinc clusters were small at n = 2-3 (2.3-4.2 kcal mol(-1)), whereas the energy increased significantly in n = 4 (9.0 kcal mol(-1)). Also, the binding nature of H2O was changed at n = 4. The cluster size dependency of the binding energy of H2O accorded well with that of the natural population of electrons in the 4p orbital of the zinc atom. In the larger clusters (n > 20), it was found that the zinc atoms in surface regions of the zinc cluster have a positive charge, whereas those in the interior region have a negative charge with the large electron population in the 4p orbital. The interaction of H2O with the zinc clusters were discussed on the basis of the theoretical results.

Theoretical Analysis of Phase-Transition Temperature of Hydrogen-Bonded Dielectric Materials Induced by H/D Isotope Effect

“…However, quantum chemical molecular orbital (MO) theory has been developed for the description of electronic motion in the molecular system. A multi-component MO (MC_MO) method [26] is proposed to the description of the nuclear motion; that is, both electronic and nuclear wave functions are calculated simultaneously and all the parameters are determined variationally, except for the physical constant [30][31][32] to express the 'optimized nuclear MO' directly.…”

“…This method is effective for the detailed geometry analysis using the potential energy surfaces. Recently, we have proposed the multi-component MO (MC_MO) method which takes into account the quantum effect of proton and deuteron directly [26]. Here, the quantum effect can include the effect of the anharmonicity due to the zero-point vibration induced by the quantum proton and deuteron.…”

Colle‐Salvetti‐type correction for electron–nucleus correlation in the nuclear orbital plus molecular orbital theory

“…Gaussian basis functions with the center on each atomic position have been adopted in molecular configurations such as equilibrium and optimized structures. Although other basis functions can be chosen in the NOMO theory, the use of the Gaussian basis functions has been widely accepted by not only our but also other groups, [11][12][13][14] probably because the conventional technologies, which have been used for molecular orbital (MO) calculations, are available. We have also developed configuration interaction singles (CIS) for the NOMO theory, 3 which allows us to calculate both the electronic and vibrational excited states.…”

Including nuclear quantum effects into highly correlated electronic structure calculations of weakly bound systems

“…37 One common characteristic of these contributions is the application of the fully variational (FV) treatment to optimize both exponents and center positions of the GTFs (and thus termed the FVMO approach 23,38,39 ). Next, Tachikawa was independently involved in further applications 40 and developments 41 of the MCMO method (see Figure 1). This way, the MCMO method approach was extended to incorporate many-body correlation effects with the FCI 41 and MP2 approaches.…”

“…Next, Tachikawa was independently involved in further applications 40 and developments 41 of the MCMO method (see Figure 1). This way, the MCMO method approach was extended to incorporate many-body correlation effects with the FCI 41 and MP2 approaches. 42 The highest accurate MCMO method, however, was developed by adopting the TRF formalism from Nakai et al 28 (see above) with the many-body correlation described at FCI level.…”