Rogério Toshiaki Kondo

Gaussian basis sets to the theoretical study of the electronic structure of perovskite (LaMnO3)

The Generator Coordinate Hartree – Fock (GCHF) method is applied to generate extended (20s14p), (30s19p13d), and (31s23p18d) Gaussian basis sets for the O, Mn, and La atoms, respectively. The role of the weight functions (WFs) in the assessment of the numerical integration range of the GCHF equations is shown. These basis sets are then contracted to [5s3p] and [11s6p6d] for O and Mn atoms, respectively, and [17s11p7d] for La atom by a standard procedure. For quality evaluation of contracted basis sets in molecular calculations, we have accomplished calculations of total and orbital energies in the Hartree– Fock – Roothaan (HFR) method for 5 MnO 1þ and 1 LaO 1þ fragments. The results obtained with the contracted basis sets are compared with values obtained with the extended basis sets. The addition of one d polarization function in the contracted basis set for O atom and its utilization with the contracted basis sets for Mn and La atoms leads to the calculations of dipole moment and total atomic charges of perovskite (LaMnO3). The calculations were performed at the HFR level with the crystal [LaMnO3]2 fragment in space group C2v: The values of dipole moment, total energy, and total atomic charges showed that it is reasonable to believe that LaMnO3 presents behaviour of piezoelectric material. q 2003 Elsevier B.V. All rights reserved.

Gaussian basis sets by generator coordinate Hartree-Fock method to ab initio calculations of electron affinities of enolates

Fed Univ Para, Ctr Ciencias Exatas & Nat, Dept Quim, Lab Quim Teor & Computac, BR-66075110 Belem, Para, Brazil

A Biblioteca Digital de Teses e Dissertações da Universidade de São Paulo

Apresentacao dos aspectos principais da Biblioteca Digital de Teses e Dissertacoes da Universidade de Sao Paulo (USP): o processo de desenvolvimento adotado para a implementacao do site, a tecnologia utilizada, a arquitetura e a funcionalidade. Discussao sobre a Biblioteca Digital no processo de pos-graduacao da USP. Relato das varias decisoes nao-tecnicas adotadas ao longo do projeto, que tiveram grande impacto no resultado final.

Development of basis sets to calculations of the electronic structure of YMnO3

Fed Univ Para, Ctr Ciencias Exatas & Nat, Dept Quim, Lab Quim Teor & Computac, BR-66075110 Belem, Para, Brazil

Contracted GTF basis sets applied to the theoretical interpretation of the Raman spectrum of hexaaquachromium(III) ion

Abstract Contracted GTF basis sets designed with aid of the Generator Coordinate Hartree–Fock (GCHF) method for H(2S), O2−(1S), and Cr3+(4F) atomic species are applied to perform theoretical interpretation of the Raman spectrum of hexaaquachromium(III) ion. The 16s, 16s10p, and 24s17p13d GTF basis sets were contracted to [4s] for H atom, [6s4p], and [9s6p3d] for O2− and Cr3+, respectively, by Dunnings scheme. For Cr3+, the [9s6p3d] basis set was enriched with f polarization function and used in combination com [4s] and [6s4p] in the study of our interest. The results obtained in this report show that the contracted GTF basis sets used are a useful alternative for the theoretical interpretation of Raman spectrum of hexaaquachromium(III) ion and that GCHF method is an effective alternative to selection of GTF basis sets for theoretical study of vibrational properties of poliatomic species.

Quantum chemical modeling of perovskite: An investigation of piezoelectricity in ferrite of yttrium

In a previous article, we used Hartree-Fock (HF) theory to study the piezoelectricity in BaTiO3. In this paper, we applied the Douglas-Kroll-Hess second order scalar relativistic method to investigate the possible piezoelectric properties in the perovskite YFeO3 structure, which has not yet been studied experimentally. The 30s20p13d and 31s21p17d Gaussian basis sets for the Fe (5D) and Y (2D) atoms, respectively, were built with the Generator Coordinate HF method. After contraction to [13s7p5d] and [13s8p7d], in combination with the 20s14p/6s4p basis set for the O (3P) atom from literature, they had their quality evaluated using calculations of the total and the orbital energies for the 2FeO+1 and 1YO+1 fragments. The dipole moment, the total energy, and the total atomic charges in YFeO3 in Cs space group were calculated. The results and the analysis lead us to believe that the perovskite YFeO3 does not present piezoelectric properties.

Design of Gaussian basis sets to the theoretical interpretation of IR-spectrum of hexaaquachromium (III) ion, tetraoxochromium (IV) ion, and tetraoxochromium (VI) ion

Fed Univ Para, Ctr Ciencias Exatas & Nat, Dept Quim, Lab Quim Teor & Computac, BR-66075110 Belem, Para, Brazil

Quantum Mechanical Approaches for Piezoelectricity Study in Perovskites

In this chapter, we show the procedures we have been used to theoretically investi‐ gate the piezoelectric effects in perovskites. The construction of extended basis sets using the generator coordinate Hartree-Fock (GCHF) method is shown, as well as the strategies used to contract extended basis sets and to evaluate their quality in molecu‐ lar calculations. Besides, we show adequate procedures to choice polarization and diffuse functions to best represent the studied crystal. In addition, we also discuss conditions under which GCHF basis sets and standard basis sets from literature can be used to theoretical investigation of piezoelectricity in perovskites. We finalize the chapter presenting and discussing the results for investigations of piezoelectricity with standard basis sets for barium and lanthanum titanates. To conclude, we present evidences that BaTiO3 and LaTiO3 may have piezoelectric properties caused by electrostatic interactions.

The digital library of historical cartography of the University of São Paulo

The Digital Library of Historical Cartography of the University of São Paulo makes available a set of high-resolution digital versions of maps printed between the XV and the XIX centuries belonging to the Universitys collections. Each map is available along with extensive carto-bibliographic and biographic references, and relevant technical, editorial and historical information for cartographic documents analysis. The Digital Library was also conceived to pursue data from other similar sites, constituting itself as a useful research tool. It provides facilities to gather relevant information to acknowledge the production, circulation and appropriation of historical maps in different contexts and media.

Quantum Mechanical Study of YTiO3 to the Investigation of Piezoelectricity

In previous articles we reported through theoretical studies the piezoelectric effect in BaTiO3, SmTiO3, and YFeO3. In this paper, we used the Douglas-Kroll-Hess (DKH) second-order scalar relativistic method to investigate the piezoelectricity in YTiO3. In the calculations we used the [6s4p] and [10s5p4d] Gaussian basis sets for the O (3P) and Ti (5S) atoms, respectively, from the literature in combination with the (30s21p16d)/[15s9p6d] basis set for the Y (3D) atom, obtained by generator coordinate Hartree-Fock (GCHF) method, and they had their quality evaluated using calculations of total energy and orbital energies (HOMO and HOMO-1) of the 2TiO