MSINDO parameterization for third‐row main group elements

A new parameterization of the SINDO model is introduced in the recently developed MSINDO version for third‐row main group elements Ga, Ge, As, Se, and Br. It is shown that the accuracy achieved for structure and stability as well as ionization potential and dipole moment of compounds containing these elements is good enough to make the extension a suitable tool for the study of larger systems. © 2000 John Wiley & Sons, Inc. J Comput Chem 21: 974–987, 2000     

Anion substitution in zinc chalcogenides

Anion substitution effects on the structure and energy of zinc chalcogenides were studied with the semiempirical molecular orbital method MSINDO. Cyclic clusters of different sizes were chosen as model systems. The convergence of the bulk properties of the perfect clusters with increasing cluster size was tested. Single and multiple substitution of oxygen atoms in zinc oxide by sulfur and of sulfur atoms in zinc sulfide by oxygen served to determine the energetics of substitution for these two cases. It was found that the substitution of oxygen by sulfur in ZnO is easier than the substitution of sulfur by oxygen in ZnS in agreement with experimental results. The interaction between two oxygen atoms vs. two selenium atoms in zinc sulfide was investigated. Oscillations of the cluster energy in dependence of the distance between the two doping atoms were observed. These are explained by the relative sites of the doping atoms in the crystal lattice. The magnitude of the oscillations is smaller in ZnS:Se than in ZnS:O, because the difference between the anion radii of S2- and Se2- is smaller than between S2- and O2-. This is also reflected in the band gap.     

Molecular dynamics investigation of water adsorption on rutile surfaces

Born-Oppenheimer molecular dynamics (MD) simulations were performed in the framework of the semi-empirical molecular orbital method MSINDO to study water adsorption on rutile surfaces. Monolayer and doublelayer water coverage was considered on the rutile (1 1 0) and (1 0 0) surfaces and the adsorbate structures were determined. Vibrational density of states of hydrogen atoms were calculated by constant temperature MD simulations at 100 K. These were used to interpret the experimental vibrational spectrum by assigning all peaks to the particular types of hydrogen atoms.     

羟基自由基与乙烯反应的化学动力学模拟

使用电子结构理论计算和直接动力学模拟对羟基自由基与乙烯反应体系进行了理论研究．在高水平的CCSD(T)/aug-cc-pVTZ//MP2/aug-cc-pVDZ上获得了包括羟基加成和氢抽取在内的多种反应通道的准确势能面信息,并在此基础上对OH+C₂H₄发展了一套准确性较高的MSINDO半经验哈密顿参数．特定反应参数哈密顿(SRP-MSINDO)能准确的再现高水平从头算结果．在2～10 kcal/mol的碰撞能应用SRP-MSINDO对OH+C₂H₄反应进行了直接准经典轨线模拟,获得的反应截面表明羟基加成反应为主导地位．另外,激发函数的模拟结果表明羟基加成是一个无势垒的捕获过程,而氢抽取则对应活化过程,这与两条反应通道的过渡态能量紧密相关．研究发现对OH+C₂H₄发展准确的半经验哈密顿需要考虑弥散矫正,这对准确描述分子间的长程吸引尤为重要     

Consistent modifications of SINDO1: I. Approximations and parameters

A consistent modification, MSINDO, of the semiempirical MO method SINDO1 is presented. Different basis sets are used for one- and two-center interactions. The treatment of the core matrix elements in the nonorthogonal basis is retained with changes only for hydrogen and 3d orbitals. Orthogonalization corrections are now restricted to nonvanishing core matrix elements in the INDO approximation. The set of atomic parameters is increased, but bond parameters are no longer used. An automatic nonlinear least-squares algorithm with a restricted step constraint is used for the optimization of parameters. Heats of formation are adjusted with inclusion of zero-point energies obtained by a scaling procedure of the force constant matrix. The present version MSINDO provides significant improvements over previous versions. A brief comparison for ground-state properties of the elements H, C, N, O, F, and Na to Cl is given. ©1999 John Wiley & Sons, Inc. J Comput Chem 20: 563–571, 1999     

MSINDO parameterization for third‐row transition metals

The recently developed MSINDO version of the semiempirical SCF MO method SINDO1 has been parameterized for third‐row transition metals Sc to Zn. The set of reference data used for the previous parameterization of SINDO1 has been substantially increased by incorporating results of recent experiments and first‐principles calculations. A comparison of calculated heats of formation, geometries, ionization potentials, and dipole moments with literature values for more than 200 gas phase molecules is presented. The accuracy of the modified MSINDO version achieved for heats of formation and bond lengths has been considerably improved compared to SINDO1. Small clusters of transition metals and metal oxides were included in the parameterization to ensure accurate results for studies of larger systems. The application of the method to small transition metal complexes that were not included in the parameterization shows that the optimized parameters are transferable to other compounds. © 2001 John Wiley & Sons, Inc. J Comput Chem 22: 861–887, 2001     

Nucleation of CuGa Phases on the MgO(100) Surface

MSINDO calculations are presented for the coadsorption of Cu and Ga atoms as clusters and islands on the MgO(100) surface. The surface is simulated by a (8 × 8 × 3) Mg₉₆O₉₆ cyclic cluster. The relative number of Cu and Ga atoms was varied in order to understand the influence of copper rich and gallium rich phases. It was found that the copper atoms have a dominating influence on the structural arrangement in mixed phases. The adsorption sites of Cu and Ga atoms are preferably O atoms, but in mixed phases these sites are usually occupied by Cu atoms.     

Molecular dynamics implementation in MSINDO: study of silicon clusters

Born-Oppenheimer molecular dynamics is implemented in the semiempirical self-consistent field molecular orbital method MSINDO. The method is employed for the investigation of the structure and dynamics of silicon clusters of various sizes. The reliability of the present parameterization for silicon compounds is demonstrated by a comparison of the results of simulated annealing and of density functional calculations of Si(n) clusters (n = 5-7). The melting behavior of the Si(7) cluster is investigated and the MSINDO results are compared to previous high-level calculations. The efficiency of the present approach for the treatment of large systems is demonstrated by an extensive simulated annealing study of the Si(45) and Si(60) clusters. New Si(45) and Si(60) structures are found and evaluated. The relative stability of various energy minimum structures is compared with density functional calculations and available literature data.