Molecular dynamic structure and dimerization of polyacetylene

The vibrational self-consistent-field approximation is used to calculate excited vibrational energy levels of the water molecule in hyperspherical coordinates. The calculations are made for a global realistic Sorbie–Murrell-type potential surface for which exactum quantum variational results are known for comparison. The coupled SCF equations are solved using the discrete variable representation (DVR ) method, which allows computation of the coupled multidimensional integrals in a very simple and efficient way. The results are in good agreement with exactum quantum calculations and are more accurate than SCF energy eigenvalues obtained using normal mode coordinates.     

Statistical simulation based on right skewed distributions

Statistical simulations in medical and biological research are usually conducted with normal random numbers. However, in many cases, the distributions of real data in medical fields are usually right skewed. The conclusions led by simulations with the misspecified model might be misleading because of a gap between real data’s distribution and theoretical one. In this paper, we provide the simulation procedure for right skewed data based on reparameterized, easily interpretable parameters of the Box–Cox transformation model which includes multivariate distributions and regression models. We also show that the provided procedure is widely applicable to real world based on laboratory data, and then we provide parameter vector sets obtained by reparameterized parameter estimates that would cover almost all situations in which the distributions of data were right skewed and unimodal.     

Dynamic stability of silacarbonyl ylide

The structure of silacarbonyl ylide in the singlet gound state is obtained by ab initio quantum chemical calculations. This proves the recent experimental observation of silacarbonyl ylide by the photolysis of oxasilitane [W. Ando, K. Hagiwara, and A. Sekiguchi, Organometallics 6, 2270 (1987)]. The dynamic stability of the silacarbonyl ylide is studied by the TCSCF /3-21G ^(*) method. The second-order Jahn-Teller effect is examined in connection with the active role of frontier orbitals. Configuration analysis is used to clarify characteristic electronic structure of the silylene-carbonyl interaction.     

Electron localization in a finite one-dimensional chain

The localization characteristics of the electronic wave functions in a finite one-dimensional chain with the diagonal or the off-diagonal disorder of the potentials have been studied. It has been shown that the eigenfuction at the frontier level is relatively “strong” against the temptation to localize caused by the existence of the random potentials. It has also been pointed out that the spatial behavior of the total density reflects that of the diagonal random potentials, but that under the off-diagonal random potentials the total density is spatially uniform (completely extended).     

Repeat space theory applied to carbon nanotubes and related molecular networks. III

The present article is part III of a series devoted to extending the Repeat Space Theory (RST) to apply to carbon nanotubes and related molecular networks. In this part III, four problems concerning the above-mentioned extension of the RST have been formulated. Affirmative solutions of these problems imply (i) asymptotic analysis of carbon nanotubes (CNTs) via the new techniques of normed repeat space, Banach algebra, and C*-algebra becomes possible; (ii) a new linkage is formed between the investigations of CNTs and those of ‘spectral symmetry’. In the present paper, we give affirmative solutions to all of the four problems, together with (a) estimates of the norms of matrix sequences representing CNTs, (b) Challenging Problem A^#, which complements Problems A, (c) several pictures of ‘CNT Matrix Art’ which has heuristic power to lead one to get the affirmative answers to the problems formulated in an abstract algebraic manner.     

Conformational analysis of thiophene-3-carbaldehyde and 3-methoxy carbonyl-thiophene

Conformational analysis of 3-substituted thiophene carbonyl derivatives, thiophene-3- carbaldehyde and 3-methoxy carbonyl thiophene has been studied by means of NMR coupling constants, carbonyl shielding effects and solvent shifts, showing that S-cis form is preferable to S-trans. Moreover, the result of a semi-empirical calculation (CNDO/2 method) suggests that the most stable conformation may be the twisted form of S-cis type even though it may not be perpendicular one. This conclusion seems to be consistent with our present experimental results and other information through IR and ultraviolet spectroscopy.     

A MO-theoretical study of the hydrogen bond in (HCOOH)2, (HCONH2)2 and (B(OH)3)2

The energy decomposition scheme is used with the ab initio MO of the STO-3G minimal basis to elucidate the nature of hydrogen-bondings in (HCOOH)₂, (HCONH₂)₂ and (B(OH)₃)₂. The comparison of the interaction energy and its five components, together with that of the difference density map, reveals the similarity or the difference of these three systems. Each component of the global difference density represents the characteristic role of the corresponding interaction. While the effect of the exchange and charge-transfer interaction is limited to the hydrogen-bonded region, that of the polarization and the coupling terms is spread over the intramolecular bonds of each monomer. The analysis of some orbital interactions is made with respect to (HCOOH)₂ and the importance of the particular charge-transfer interaction is demonstrated.     

Interaction of tea CO2 laser light with plasma

High power double discharge type TEA CO₂ laser was used to study laser plasma interaction on carbon target plasma. The maximum output power was 0.3 GW and full width at half maximum intensity was 100 ns. We measured the reflectivity of the laser light at 10.6 μm in wavelength from the carbon plasma. The reflectivity showed a maximum (≈56%) at the laser power intensity of about 1.1 x 10¹⁰ W/cm², and at above this value, the reflectivity decreased. The absorption was introduced effectively above this intensity. The electron density and temperature were also measured.