Molecular orbital theory of the properties of inorganic and organometallic compounds. 3. STO-3G basis sets for first- and second-row transition metals

STO -3G minimal basis sets for first- and second-row transition metals have been formulated and applied to the calculation of equilibrium geometries for a variety of inorganic systems, metal carbonyls, and organometallic compounds. While the overall level of agreement with experiment is not as good as that previously noted for main-group compounds, most trends and many subtle features in geometries are reproduced.     

Basis sets for geometry optimizations of second-row transition metal inorganic and organometallic complexes

Modest-sized basis sets for the second-row transition metal atoms are developed for use in geometry optimization calculations. Our method is patterned after previous work on basis sets for first-row transition metal atoms. The basis sets are constructed from the minimal basis sets of Huzinaga and are augmented with a set of diffuse p and d functions. The exponents of these diffuse functions are chosen to minimize both the difference between the calculated and experimental equilibrium geometries and the total molecular energies for several second-row transition metal inorganic and organon etallic complexes. Slightly smaller basis sets, based on the same Huzinaga minimal sets but augmented with a set of diffuse s and p functions rather than diffuse p and d functions, are also presented. The performance of these basis sets is tested on a wide variety of second-row transition metal inorganic and organometallic complexes and is compared to pseudopotential basis sets incorporating effective core potentials.     

Atomic natural orbital basis sets for transition metals

Summary We show that atomic natural orbitals are an excellent way to contract transition-metal basis sets, even though the different low-lying electronic states may have very different basis set requirements.     

Indo parameters for the first-and second-row transition metals

A system of INDO parameters F⁰(ij) and U_ii for the first-and second-row transition metals is proposed. The system correctly reproduces the energies of the lowest terms of dⁿ, dⁿ⁻¹s, dⁿ⁻²s², dⁿ⁻¹p, and dⁿ⁻²sp configurations of M⁰ atoms and M¹⁺ ions. The parameters are estimated from spectroscopic values of energies of the terms and F^k(ij) and G^k(ij) parameters. St. Petersburg State University. Translated fromZhurnal Strukturnoi Khimii, Vol. 35, No. 4, pp. 3–11, July–August, 1994. Translated by O. Kharlamova     

Reduced-size polarized basis sets for calculations of molecular electric properties. IV. First-row transition metals

Recent studies of the perturbation-dependent basis sets have indicated the possibility of a significant reduction of the size of the usual CGTO sets without considerable loss of accuracy in calculations of molecular electric properties. The resulting (ZPolX) basis sets have been developed for several atoms of the first and second row of the Periodic Table. The same method of the ZPolX basis set generation is extended for the first-row transition metals and the corresponding contracted ZPolX basis sets of the size [6s5p3d1f] are determined for both nonrelativistic and scalar relativistic calculations. The performance of the ZPolX basis sets is verified in calculations on the first-row transition metal oxides at the level of the ROHF, ROHF/CASPT2, and ROHF/CCSD(T) approximations. Also the study of the dipole polarizability of TiCl₄ confirms the excellent features of these very compact basis sets. The ZPolX basis sets for nonrelativistic and relativistic calculations of molecular electric properties are available on the web page http://www.chem.uni.torun.pl/zchk/basis-sets.html.     

Gaussian basis sets for transition metals of the second series

A Gaussian basis set consisting of (15s, 9p, 8d) Gaussian functions has been optimized for the transition metal atoms of the second series (fourth-row atoms).     

Large atomic natural orbital basis sets for the first transition row atoms

Large atomic natural orbital (ANO) basis sets are tabulated for the Sc to Cu atoms. The primitive sets are taken from the large sets optimized by Partridge, namely (21s13p8d) for Sc and Ti and (20s12p9d) for V to Cu. These primitive sets are supplemented with threep, oned, sixf, and fourg functions. The ANO sets are derived from configuration interaction density matrices constructed as the average of the lowest states derived from the 3d ⁿ 4s ² and 3d ⁿ⁺¹4s ¹ occupations. For Ni, the¹ S(3d ¹⁰) state is included in the averaging. The choice of basis sets for molecular calculations is discussed.     

Calculation of exchange coupling constants in solid state transition metal compounds using localized atomic orbital basis sets

The application of theoretical methods based on density functional theory using hybrid functionals and localized, atomic orbital type basis sets is shown to provide good estimates for exchange coupling constants in non-metallic, solid state transition metal compounds with relatively complex crystal structures. The accuracy of the calculated exchange coupling constants is similar to that previously obtained for dinuclear and polynuclear molecular compounds. As an application of this procedure, the magnetic properties of the high-temperature phase of CuGeO₃, the recently synthesized silver copper oxide Ag₂Cu₂O₃, and the family of M[N(CN)₂]₂ (M=Cr(II), Mn(II), Fe(II), Co(II), Ni(II) and Cu(II)) compounds are analyzed via the computation of their most relevant exchange coupling constants.     

Semiempirical calculations of the electronically excited states of organometallic compounds: Selection of configuration interaction basis sets

Semiempirical INDO-E/S+RCIP calculations of the electronic structures of the ground and excited states of the pyrazine (pz) molecule and [Ru(NH₃)₅pz]^q (q=+1, +2, +3) complexes were performed to analyze the dependence of the calculation results on the active MO space and configuration basis set. Recommendations for the construction of the {Ф_k} basis sets and formation of the {ϕ_k} sets are given. St. Petersburg State University. Translated fromZhurnal Struktumoi Khimii, Vol. 37, No. 2, pp. 206–219, March–April, 1996. Translated by I. Izvekova     

Thermal decomposition of inorganic and organometallic compounds of tin-I. Triphenyltin hydroxide

The thermal decomposition of triphenyltin hydroxide in the temperature range 25–400°C has been studied. The decomposition products formed at each stage have been isolated and characterised. A decomposition scheme involving a reductive-elimination reaction is proposed. The proportions of this reaction and the accompanying reaction are dependent on the mode of heating.     

Non-empirical calculations on diatomic transition metals. I. An investigation of various orbital contraction schemes of gaussian basis sets on the SCF level for Zn2

Ab initio SCF LCAO MO calculations with various contracted primitive gaussian basis sets were performed using Zn₂ as an example. When improving the basis set, polarization functions are shown to be more important for a proper reproduction of the repulsive potential curve, than a complete relaxation of the orbital contraction. This is considered to be true for all diatomics although for Zn₂ at larger internuclear distances no varr der Waals minimum is obtained on the SCF level.     

Reduced hamiltonian orbitals. II. Optimal orbital basis sets for the many-electron problem

Optimal orbital exponents are approximated by minimization of the reduced Hamiltonian orbital ground state energy. They appear to be as good as and are obtained at much less expense than the values derived by the usual SCF exponent optimization scheme. Partitioning of energy into 0-energy, 1-energy, and 2-energy (Absar and Coleman, Int. J. Quant. Chem. 10 , 319 (1976); Chem. Phys. Lett. 39 , 60 (1976)) is used to study the variation in the electronic energy surface upon variation of orbital exponents. The 1-energy operator, the natural orbitals of which are the reduced Hamiltonian orbitals, is compared with the SCF operator.