Hiroyuki Kawabe

Superconducting and other phases in organic high polymers of polyacenic carbon skeletons. I. The method of sum of divergent perturbation series

The instabilities of a normal molecular orbital state of polyacenic materials are studied within RPA with a g model for an electronic interaction. The condensed states predicted are singlet superconducting (SSC), charge density wave (CDW), and spin density wave (SDW) ones, and their phase diagram is shown. In contrast to usual one‐dimensional (1D) conductors, there reveals a wide range of superconducting state, which is not overcome by CDW transition. Weakness of Peierls distortion of the present model is also contrasted with the case of polyacetylene.

Theoretical Auger electron spectra of polymers by density functional theory calculations using model dimers.

We propose a new approach for analysis of Auger electron spectra (AES) of polymers by density functional theory (DFT) calculations with the Slaters transition‐state concept. Simulated AES and X‐ray photoelectron spectra (XPS) of four polymers [(CH2CH2)n (PE), (CH2CH(CH3))n (PP), (CH2CH(OCH3))n (PVME), and (CH2CH(COCH3))n (PVMK)] by DFT calculations using model dimers are in a good accordance with the experimental ones. The experimental AES of the polymers can be classified in each range of 1s–2p2p, 1s–2s2p, and 1s–2s2s transitions for C KVV and O KVV spectra, and in individual contributions of the functional groups from the theoretical analysis.

PATH INTEGRAL METHOD BY MEANS OF GENERALIZED COHERENT STATES AND ITS NUMERICAL APPROACH TO MOLECULAR SYSTEMS. I. ENSEMBLE AVERAGE OF TOTAL ENERGY

A path integral formulation by the generalized coherent states of the Thouless parameterization is presented to apply to molecular systems. Explicit expressions of the ensemble average of the physical property including the spin space is also derived. In order to compute the ensemble average, a novel calculating scheme is shown. The Monte Carlo method by the metropolis algorithm is used, and in order to avoid the negative sign problem, a reweighting method is attempted. Simple examples are examined to demonstrate performances of calculations. We discussed in relation to the total energy and the number of the division for the partition function or the temperature.

Theoretical Auger electron and X-ray emission spectra of CO and H2O by density functional theory calculations

Abstract We propose a new method for analysis of X-ray emission and Auger electron spectra (XES and AES) of molecules involving the valence spectra using density functional theory (DFT) calculations. To obtain the more accurate transition energies and the relative intensities, we use the total-energy difference procedure ( ΔE -KS) for all transition energies, and transform the coefficients in the LCGTO-MO scheme in the DFT to those for the linear combination of the LCGTO-AO scheme. The method is applied to the analysis of valence spectra, XES and AES for CO and H 2 O molecules. The simulated spectra are in a good agreement with the experimental results.

Theoretical studies on anomalous phases in model plane systems of LiBeH3

Abstract The possibility of the charge-mediated superconductivity in LiH and BeH2 plane systems was studied by means of the Greens function method and a numerical approach. It is unlikely that the effective electron-electron interaction for these systems becomes attractive.

THEORETICAL STUDIES ON MANY-BAND EFFECTS IN SUPERCONDUCTIVITY BY USING RENORMALIZATION GROUP APPROACH

We present a renormalization equations for two-band superconductivity by using a two-band model and present phase diagrams for the two-band superconductivity. In the framework of two-band model, the present results predict that superconductivity appears, even if electron-electron interaction is positive. We discuss the possibility of a cooperative mechanism in the two-band superconductivity in relation to high-Tc superconductivity.

Nonadiabatic Treatment of Molecular Systems by the Wavepackets Method

ABSTRACT = We have already developed the many-electron wavepackets (MEWP) method in order to study the dynamics and electronic structure of molecular systems. We extended the MEWP method to study the nonadiabatic effects and formulated a nonadiabatic molecular theory, where both electron and nucleus are treated equivalently. Then we applied our method to the isotope series of hydrogen molecule i.e., H,, HD, and D,, and calculated the total energy and the average distance between nucleus-nucleus, electron-electron, and nucleus-electron in order to analyze numerically the nonadiabatic effect in the molecule. Finally we calculated the real-time evolution of the polarization by means of Chebyshev scheme; and by Fourier transforming this, we found out the excitation spectrum of the system, which corresponds to the electronic excitation and the nuclear vibrational frequency. 0 1996 John Wiley & Sons, Inc. International Journal of Quantum Chemistry: Quantum Chemistry Symposium 30, 1261 -1270 (1 996) 0 1996 John Wiley & Sons, Inc. CCC 0360-8832 I96 I071 261 -1

Theoretical study on magnetic structures of noncollinear magnets

The valence energy of Ru 2 O and Ru 2 is calculated for several spin multiplicity by the Hartree-Fock theory and the density functional theory. The noncollinear spin structure is also calculated for the H 3 molecule at the equilateral triangle by the variational Monte Carlo method using the general spin orbital.

CALCULATION OF MAGNETIZATION BY PATH INTEGRAL METHOD I

Abstract The path integral method is formulated by means of the extended Thouless parametrization. The ab initio Hamiltonian and the Zeeman Hamiltonian are used in our model systems. Numerical calculation of physical properties of molecules is performed in terms of the Monte Carlo method. The dependence of the magnetization of a hydrogen molecule on the division for the partition function, the temperature and the external magnetic field is discussed.

The Support System for a Visual Impaired Person Using Laser Eyewear

We construct a system for a visually impaired person. On our system, an image is input by a camera, is transformed by an image conversion system, and is provided to the visually impaired person by an eyewear like glasses. If this system is used, a person can move with the eyewear, and also can watch a scene in the position of line of sight. In the eyewear composed of our system, which is made by QDLaser Inc., the image is projected directly onto a retina. QDLaser Inc. has worked on a small-sized scanning optics to be installed inside the glass frame, and has developed the eyewear named Retinal Imaging Laser Eyewear with the trademark of RETISSA. One of remarkable features of RETISSA is focus free. Regardless of the function of a crystalline lens and eyesight, the wearer can see laser scanned full-color image captured by a digital camera installed in the center of the frame connected to a controller. One of other features of RETISSA is an attractive appearance of eyewear. RETISSA also enables universal design like sunglasses and corrective glasses and realizes complete AR. We explain the system and this eyewear.