Generation of subpicosecond vacuum ultraviolet pulses at 126 nm by using harmonics of a subpicosecond Ti:Sapphire laser

Subpicosecond vacuum ultraviolet (VUV) pulses at the wavelength of 126 nm have been generated in rare gases as a result of the 7th harmonic radiation of a subpicosecond Ti:Sapphire laser oscillating at 882 nm. The VUV harmonic intensity was optimized in Xe at the pressure of 1.2 Torr. The behavior of the harmonic emission was qualitatively reproduced by the classical nonlinear optics. The increase of the harmonic intensity was limited by multiphoton ionization of Xe.     

Charge Transfer Transitions from Cyclohexadienyl-Type Radicals to Host Molecules in Anthracene Single Crystals

The optical absorption spectra of 1-, 2- and 9-dibenzo-cyclohexadienyl radical in anthracene crystals have been obtained and analyzed. It is shown that the absorption lines consist of vibrational progression and charge-transfer lines for 2- and 9-DBCR. Each line belonging to the former has the same polarization as the most intense 0–0 vibrational line and the latter show polarization character depending on the direction of charge transfer and the transition energy was found to have a coulombic dependence on the distance of charge transfer. It is pointed out that only charge transfer lines were observed for 1-DBCR. The splitting of lines were observed and ascribed either to the resonance transfer interaction between two neighboring molecules situated at an equal distance from the radical or to the site symmetry. It is suggested that the intensity of the charge-transfer lines are borrowed from the intra-radical transition. The result that the charge transfer lines are more intense than the intra-radical lines for 1-DBCR was discussed.     

Manganese centers with various valency in alkali halides

Abstract

Optical absorption bands and epr spectra of NaCl: Mn⁺⁺ X-irradiated at liquid nitrogen and room temperature are studied. Manganese epr spectra are divided into three classes, based on the value of hyperfme splitting constants. It is shown that the epr spectra with the hyperhe splitting constants of around 250 × 10-⁴, 80 × 10^?4 and 20 × 10^?4 cm^?1 are caused by Mn⁺, Mn⁺⁺ and Mn⁹, respectively. Formation of several manganese centers by X-irradiation is discussed. It is suggested that optical absorption bands at 410 and 440 nm are caused by Mn^O at the lattice site and that the Mn^O center which gives an epr spectrum with A = 15. 5 × 10^?4 cm^?1 is associated with a Mn⁰ center which is not at a substitutional site.     

Empirical determination of the random fraction in disordered channel

A new method of deriving the random fraction in a disordered channel : rom dechanneling experiments is described. In this method backscattering spectra obtained at two different doses are employed, with an assumption on the dose dependence of the defect concentration. The method is applied to the experimental data for B-implanted Si and it is found that the obtained random fraction is similar to the result of the diffusion calculation made by the present authors. The depth profiles of defects are also obtained and compared with the result of theoretical calculations.     

Soot formation characteristics in a lab-scale turbulent pulverized coal flame with simultaneous planar measurements of laser induced incandescence of soot and Mie scattering of pulverized coal

Soot formation characteristics of a lab-scale pulverized coal flame were investigated by performing carefully controlled laser diagnostics. The spatial distributions of soot volume fraction and the pulverized coal particles were measured simultaneously by laser induced incandescence (LII) and Mie scattering imaging, respectively. In addition, the radial distributions of the soot volume fraction were compared with the OH radical fluorescence, gas temperature and oxygen concentration obtained in our previous studies [1], [2]. The results indicated that the laser pulse fluence used for LII measurement should be carefully controlled to measure the soot volume fraction in pulverized coal flames. To precisely measure the soot volume fraction in pulverized coal flames using LII, it is necessary to adjust the laser pulse fluence so that it is sufficiently high to heat up all the soot particles to the sublimation temperature but also sufficiently low to avoid including a too large of a change in the morphology of the soot particles and the superposition of the LII signal from the pulverized coal particles on that from the soot particles. It was also found that the radial position of the peak LII signal intensity was located between the positions of the peak Mie scattering signal intensity and peak OH radical signal intensity. The region, in which LII signal, OH radical fluorescence and Mie scattering coexisted, expanded with increasing height above the burner port. It was also found that the soot formation in pulverized coal flames was enhanced at locations where the conditions of high temperature, low oxygen concentration and the existence of pulverized coal particles were satisfied simultaneously.     

Study of the Three-Nucleon Force Effects in the 2H(p, n) Breakup Reaction at 170 MeV

For the study of three nucleon force (3NF) effects in the intermediate energy region, the differential cross sections and the vector analyzing power A _y were measured for the ²H(p, n) inclusive breakup reaction at 170 MeV. The polarized proton beam of 170 MeV was injected to the deuterated polyethylene (CD₂) target and the energy of scattered neutrons were deduce by TOF method. The data was compared with the results of the Faddeev calculations with and without 3NFs. Concerning about the differential cross sections, we can see large discrepancies between the data and the calculations in the region where the energies of scattered neutrons are low, which are similar to the results of the ²H(p, p) inclusive breakup reaction at 250 MeV.     

Representations of (α, β, γ) triple system

We introduce a notion of (α, β, γ) triple system which generalizes the familiar generalized Jordan triple system. We then discuss its realization by some bilinear algebras and vice versa. We also give a characterization of the structurable algebra of Allison in terms of (?1, 1) Freudenthal–Kantor triple system by imposing some additional triple product constraints.     

Characterization of atmospheric tritiated water concentration in the vicinity of the fukushima daiichi nuclear power plant

Journal of Radioanalytical and Nuclear Chemistry - This paper discusses the spatiotemporal variation in atmospheric tritiated water (HTO) concentration near the Fukushima Daiichi Nuclear Power...     

Synthesis and Diverse Transformations of a Dinitrogen Dititanium Hydride Complex Bearing Rigid Acridane-Based PNP-Pincer Ligands

Studies on N₂ activation and transformation by transition metal hydride complexes are of particular interest and importance. The synthesis and diverse transformations of a dinitrogen dititanium hydride complex bearing the rigid acridane-based ^acriPNP-pincer ligands {[(^acriPNP)Ti]₂(μ₂-η¹:η²-N₂)(μ₂-H)₂} are presented. This complex enabled N₂ cleavage and hydrogenation even without additional H₂ or other reducing agents. Furthermore, diverse transformations of the N₂ unit with a variety of organometallic compounds such as ZnMe₂, MgMe₂, AlMe₃, B(C₆F₅)₃, PinBH, and PhSiH₃ have been well established at the rigid ^acriPNP-ligated dititanium framework, such as reversible bonding-mode change between the end-on and side-on/end-on fashions, diborylative N=N bond cleavage, the formal insertion of two dimethylaluminum species into the N=N bond, and the formal insertion of two silylene units into the N=N bond. This work has revealed many unprecedented aspects of dinitrogen reaction chemistry.     

Solvent-controlled dehydration and diastereoselective formation of indenone-fused thiazolo[3,2-a]pyridines via a one-pot four-component reaction

A solvent-controlled four-component reaction has been described for the preparation of either hydroxy-tetrahydro-thiaza-cyclopenta[c]fluoren-6-one or dihydro-thiaza-cyclopenta[c]fluoren-6-one from nitroketene dithioacetals, cysteamine hydrochloride, 1,3-indandione and aromatic aldehydes starting materials by changing solvent systems. These reactions proceed under catalyst-free conditions affording a range of two types of skeletally distinct thiazolo[3,2-a]pyridines-based heterocycles. Hydroxy-tetrahydro-thiaza-cyclopenta[c]fluoren-6-one was obtained in H₂O/EtOH (3:1, v/v) in high yield and diastereoselectivity but in contrast dihydro-thiaza-cyclopenta[c]fluoren-6-one was synthesised in EtOH in moderate to good yields and in the longer reaction time. The structural diversities have been confirmed spectroscopically, by IR ¹H and ¹³C NMR, and EI-MS spectra, which agree with the proposed structures.