15 results match your criteria: "Kyoto Technoscience Center 16[Affiliation]"

Exact Theory Applied to the Lithium Atom.

J Chem Theory Comput

September 2024

Quantum Chemistry Research Institute, Kyoto Technoscience Center 16, 14 Yoshida Kawaramachi, Sakyo-ku, Kyoto 606-8305, Japan.

Article Synopsis
  • The free complement (FC) theory was used to solve the scaled Schrödinger equation (SSE) for the lithium atom, allowing for accurate calculation of wave functions, energies, and properties of its ground and excited states.
  • The methodology addresses issues of divergence found in traditional variational methods by using a specific scaling function, demonstrating the effectiveness of FC theory for a three-electron system.
  • Results showed high agreement with experimental and previously reported theoretical values, confirming the ability of the exact theory to provide precise solutions.
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In a previous paper [. 030403.], one of the authors introduced the scaled Schrödinger equation (SSE), ( - )ψ = 0 for atoms and molecules, where the scaling function is the positive function of the electron-nuclear (e-n) and electron-electron (e-e) distances.

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The potential energy curves (PECs) of the low-lying five Σ and Π states (XΣ, CΣ, 3Σ, AΠ, and DΠ states) of a CH molecule, an important interstellar molecule, were calculated by the free complement (FC) - local Schrödinger equation (LSE) theory with the direct local sampling scheme. The FC wave functions were constructed based on the chemical formula theory (CFT), whose local characters correspond to the covalent dissociations: C(P°(sp))) + H(S) of the XΣ and AΠ states and the ionic dissociations: C(D(sp)) + H of the CΣ and DΠ states. All the calculated PECs were obtained with satisfying the chemical accuracy, i.

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Gaussian functions with odd power of r produced by the free complement theory.

J Chem Phys

July 2023

Quantum Chemistry Research Institute, Kyoto Technoscience Center 16, 14 Yoshida Kawara-machi, Sakyo-Ku, Kyoto 606-8305, Japan.

Article Synopsis
  • The paper focuses on the r-Gaussian function, which is crucial for solving the Schrödinger equation for Gaussian-based functions in quantum chemistry.
  • These rG functions enhance the accuracy of wave functions, especially in regions close to the atomic nucleus (cusp region), making them essential for precise calculations.
  • To compute integrals for multi-centered rG functions, the authors introduce the rG-NG expansion method, demonstrating its effectiveness through applications like the hydrogen molecule.
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The free-complement (FC) theory proposed for solving the Schrödinger equation of atoms and molecules highly accurately was applied to the calculations of the potential curves of the lower nine states of the Li molecule. The results were compared with the accurate experimental Rydberg-Klein-Rees potential curves available. They overlap completely with each other without any shift everywhere for all the states of Li.

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Accurate scaling functions of the scaled Schrödinger equation.

J Chem Phys

January 2022

Quantum Chemistry Research Institute, Kyoto Technoscience Center 16, 14 Yoshida Kawara-machi, Sakyo-ku, Kyoto 606-8305, Japan.

The scaling function g of the scaled Schrödinger equation (SSE) is generalized to obtain accurate solutions of the Schrödinger equation (SE) with the free complement (FC) theory. The electron-nuclear and electron-electron scaling functions, g and g, respectively, are generalized. From the relations between SE and SSE at the inter-particle distances being zero and infinity, the scaling function must satisfy the collisional (or coalescent) condition and the asymptotic condition, respectively.

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Article Synopsis
  • The study revisits the Σ states of the hydrogen molecule, utilizing the free complement (FC) variational method to solve the Schrödinger equation for both ground and excited Π states.
  • This method provides highly accurate energy calculations and ensures the potential energy curves depict proper dissociation behavior.
  • Additionally, vibrational energy levels for each state were determined by solving the vibrational Schrödinger equation based on the precise potential energy curves obtained.
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Light-Driven Proton, Sodium Ion, and Chloride Ion Transfer Mechanisms in Rhodopsins: SAC-CI Study.

J Phys Chem A

March 2019

Quantum Chemistry Research Institute , Kyoto Technoscience Center 16, 14 Yoshida Kawara-machi , Sakyou-ku, Kyoto 606-8305 , Japan.

Bacteriorhodopsin (BR) and halorhodopsin (HR) are well-known light-driven ion-pumping rhodopsins. BR transfers a proton from the intracellular medium to the extracellular medium. HR takes in chloride ion from the extracellular medium.

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The chemical formula theory (CFT) proposed in Paper I of this series [H. Nakatsuji et al., J.

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The free-complement (FC) theory for solving the Schrödinger equation (SE) was applied to calculate the potential energy curves of the ground and excited states of the hydrogen molecule (H) with the Σ , Σ , Σ , Σ , Π, Π, Π, Π, Δ, Δ, Δ, Δ, Φ, Φ, Φ, and Φ symmetries (in total, 54 states). The initial functions of the FC theory were formulated based on the atomic states of the hydrogen atom and its positive and negative ions at the dissociation limits. The local Schrödinger equation (LSE) method, which is a simple sampling-type integral-free methodology, was employed instead of the ordinary variational method and highly accurate results were obtained stably and smoothly along the potential energy curves.

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The Schrödinger equation of hydrogen molecules was solved essentially exactly and systematically for calculating the potential energy curves of the electronic ground and excited states of the Σ, Σ, Σ, and Σ symmetries. The basic theory is the variational free complement theory, which is an exact general theory for solving the Schrödinger equation of atoms and molecules. The results are essentially exact with the absolute energies being correct beyond μ-hartree digits.

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Photoelectron spectrum of NO : SAC-CI gradient study of vibrational-rotational structures.

J Comput Chem

January 2019

Quantum Chemistry Research Institute, Kyoto Technoscience Center 16, 14 Yoshida Kawara-machi, Sakyou-ku, Kyoto 606-8305, Japan.

Article Synopsis
  • Three-dimensional potential energy surfaces for NO and NO were calculated using the SAC/SAC-CI method, allowing for the analysis of various properties.
  • The computed electron affinity matched experimental values fairly well, and the photoelectron spectra at 350 K and 700 K were successfully predicted, showing the importance of rotational effects.
  • The theoretical results aligned with previous experimental findings while revealing additional contributions from the asymmetric-stretching mode of NO.
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Article Synopsis
  • The free-complement chemical-formula theory (FC-CFT) was applied to the Schrödinger equation, achieving high accuracy in calculating the ground state of first-row atoms and small molecules.
  • A local Schrödinger equation method was used to ensure stable and precise solutions, alongside a combined sampling technique that included local and Metropolis sampling for improved quantum mechanical calculations.
  • The methodology demonstrates consistent accuracy and stability, indicating its potential as a valuable tool for solving the Schrödinger equation for various atoms and molecules, although further testing on the stationarity principle is needed.
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Chemistry is governed by the principle of quantum mechanics as expressed by the Schrödinger equation (SE) and Dirac equation (DE). The exact general theory for solving these fundamental equations is therefore a key for formulating accurately predictive theory in chemical science. The free-complement (FC) theory for solving the SE of atoms and molecules proposed by one of the authors is such a general theory.

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Accuracy of Td-DFT in the Ultraviolet and Circular Dichroism Spectra of Deoxyguanosine and Uridine.

J Phys Chem A

January 2018

Quantum Chemistry Research Institute, Kyoto Technoscience Center 16, 14 Yoshida Kawara-machi, Sakyou-ku, Kyoto 606-8305, Japan.

Accuracy of the time-dependent density functional theory (Td-DFT) was examined for the ultraviolet (UV) and circular dichroism (CD) spectra of deoxyguanosine (dG) and uridine, using 11 different DFT functionals and two different basis sets. The Td-DFT results of the UV and CD spectra were strongly dependent on the functionals used. The basis-set dependence was observed only for the CD spectral calculations.

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