月別: 2022年12月

[Published online Journal of Computer Chemistry, Japan Vol.21, 52-54, by J-STAGE]
<Title:> 密度汎関数法におけるSCF計算条件の最適化による高速化
<Author(s):> 大田　栄二, 白幡　晃一, 石川　敦之
<Corresponding author E-Mill:> eiji(at)fujitsu.com
<Abstract:> Density functional theory (DFT) is a successful theory for calculating the electronic structure of atoms, molecules, and solids. However, in modern computing environments is difficult significantly improve the computational efficiency of DFT. Acceleration of DFT requires optimization of the computational algorithms. We demonstrate two acceleration methods by optimization of the computational algorithms that optimize parallel parameters for eigenvalue calculations and optimization of convergence conditions for the self-consistent field (SCF) calculation.
<Keywords:> Density functional theory, Self-consistent field, Eigenvalue calculation, Convergence conditions, Optimization
<URL:> https://www.jstage.jst.go.jp/article/jccj/21/2/21_2022-0027/_article/-char/ja/

[Published online Journal of Computer Chemistry, Japan -International Edition Vol.8, -, by J-STAGE]
<Title:> A Tautomerization Software Based on Lewis Structures and Reaction Mechanisms
<Author(s):> Ming YU
<Corresponding author E-Mill:> yuming086(at)gmail.com
<Abstract:> A new method is proposed to translate molecule Lewis structures to machine-readable format data and a software based on Lewis structures has been developed to simulate the practice of chemists writing tautomerization mechanisms. For a tautomeric compound, from one Lewis formula entered by users, the software can generate its other equivalent tautomer (s), which share a common tautomerization intermediate stabilized by resonance. Not only atom balance but also electron balance are guaranteed in the tautomerism representation. The stereochemistry changes caused by tautomeric equilibrium can be tracked too. All the stereoisomers for the compounds containing tetrahedral carbon stereocenters and double bond stereocenters can be identified.
<Keywords:> Tautomerization, Software, Stereochemistry, Lewis structure, Mechanism
<URL:> https://www.jstage.jst.go.jp/article/jccjie/8/0/8_2021-0050/_html

[Published online Journal of Computer Chemistry, Japan -International Edition Vol.8, -, by J-STAGE]
<Title:> Calculus of Several Harmonic Functions
<Author(s):> Kazuhiro ISHIDA
<Corresponding author E-Mill:> k-ishida(at)fancy.ocn.ne.jp
<Abstract:> Abstract: We describe several harmonic functions; the solid harmonics (SH), the mixed SH, the reducing SH and the reducing mixed SH. We do the solid harmonic gradient (SHG) operator. Using the SHG, we derive a new Gauss-transform and a new Fourier-transform for real-type general Slater-type orbitals (STO). Several formulas can be derived for the calculus of harmonic functions. They will be useful especially for evaluating the angular part of molecular integrals over STOs and over Gaussian-type orbitals with higher-angular-momenta.Keywords: Several harmonic functions; Molecular integrals; Solid harmonics; Higher-angular-momenta; Slater-type orbital; Solid harmonic gradient.
<Keywords:>
<URL:> https://www.jstage.jst.go.jp/article/jccjie/8/0/8_2021-0029/_html