Absolute measurements of anomalous small-angle X-ray scattering intensity using glassy carbon at the Mg K absorption edge

Absolute measurements of small-angle X-ray scattering (SAXS) intensities at the K absorption edge of Mg have been performed using glassy carbon as an intensity standard. Glassy carbon samples polished down to give appropriate transmission have been prepared as a secondary standard to be used at 1.3 keV. Al–Mg binary alloys were used to assess the metastable phase boundary for the Al3Mg metastable precipitation from the absolute scattering intensity. The assessed phase boundary agreed with the previous reports. Glassy carbon was concluded to be an appropriate candidate for an intensity standard sample for transmission measurements of SAXS in the tender X-ray regions

Investigation of organic matter in the Allende meteorite using scanning transmission X-ray microscope at photon factory

第6回極域科学シンポジウム[OA] 南極隕石11月16日（月）　国立極地研究所１階交流アトリウ

Ion desorption from molecules condensed at low temperature: A study with electron-ion coincidence spectroscopy combined with synchrotron radiation

This article reviews our recent work on photo-stimulated ion desorption (PSID) from molecules condensed at low temperature. We have used electron-ion coincidence (EICO) spectroscopy combined with synchrotron radiation. The history and present status of the EICO apparatus is described, as well as our recent investigations of condensed H₂O, NH₃, CH₃CN, and CF₃CH₃. Auger electron photoion coincidence (AEPICO) spectra of condensed H₂O at the O:1s ionization showed that H⁺ desorption was stimulated by O:KVV Auger processes leading to two - hole states (normal- Auger stimulated ion desorption (ASID) mechanism). The driving forces for H⁺ desorption were attributed to the electron missing in the O - H bonding orbitals and the effective hole-hole Coulomb repulsion. The normal ASID mechanism was also demonstrated for condensed NH₃. The H⁺ desorption at the 4a₁ ← O(N):1s resonance of both condensed H₂O and condensed NH₃ was found to be greatly enhanced. Based on the AEPICO spectra the following four-step mechanism was proposed: (1) the 4a₁ ← 1s transition, (2) extension of the HO - H (H₂N - H) distance within the lifetime of the (1s)⁻¹(4a1)¹ state, (3) spectator Auger transitions leading to (valence)⁻²(4a₁)¹ states, and (4) H⁺ desorption. The enhancement of the H⁺ desorption yield was attributed to the repulsive potential surface of the (1s) - 1(4a₁)¹ state. At the 3p ← O:1s resonance of condensed H₂O, on the other hand, the H⁺ yield was found to be decreased. The AEPICO spectra showed that the H⁺ desorption was stimulated by spectator Auger transitions leading to (valence)⁻²(3p)¹ states. The decrease in the H⁺ yield was attributed to a reduction in the effective hole-hole Coulomb repulsion due to shielding by the 3p electron. Photoelectron photoion coincidence (PEPICO) spectra of condensed H₂O showed that the core level of the surface H₂O responsible for the H⁺ desorption was shifted by 0.7 eV from that of the bulk H₂O. The H⁺ desorption from condensed CH₃CN was also investigated. In a study of condensed CF₃CH₃ using PEPICO spectroscopy, site-specific ion desorption was directly verified; that is, H⁺ and CH₃⁺ desorption was predominant for the C:1s photoionization at the -CH₃ site, while C₂Hn⁺, CFCHm⁺, and CF₃⁺ desorption was predominantly induced by the C:1s photoionization at the -CF₃ site. These investigations demonstrate that EICO spectroscopy combined with synchrotron radiation is a powerful tool for studying PSID of molecules condensed at low temperature

Heating Experiments of the Tagish Lake Meteorite: Investigation of the Effects of Short-Term Heating on Chondritic Organics

We present in this study the effects of short-term heating on organics in the Tagish Lake meteorite and how the difference in the heating conditions can modify the organic matter (OM) in a way that complicates the interpretation of a parent body's heating extent with common cosmo thermometers. The kinetics of short-term heating and its influence on the organic structure are not well understood, and any study of OM is further complicated by the complex alteration processes of the thermally metamorphosed carbonaceous chondrites - potential analogues of the target asteroid Ryugu of the Hayabusa2 mission - which had experienced post-hydration, short-duration local heating. In an attempt to understand the effects of short-term heating on chondritic OM, we investigated the change in the OM contents of the experimentally heated Tagish Lake meteorite samples using Raman spectroscopy, scanning transmission X-ray microscopy utilizing X-ray absorption near edge structure spectroscopy, and ultra-performance liquid chromatography fluorescence detection and quadrupole time of flight hybrid mass spectrometry. Our experiment suggests that graphitization of OM did not take place despite the samples being heated to 900 degrees Centigrade for 96 hours, as the OM maturity trend was influenced by the nature of the OM precursor, such as the presence of abundant oxygenated moieties. Although both the intensity of the 1s-sigma * exciton cannot be used to accurately interpret the peak metamorphic temperature of the experimentally heated Tagish Lake sample, the Raman graphite band widths of the heated products significantly differ from that of chondritic OM modified by long-term internal heating

Fullerene mixing effect on carrier formation in bulk-hetero organic solar cell

Organic solar cells (OSCs) with a bulk-heterojunction (BHJ) are promising energy conversion devices, because they are flexible and environmental-friendly, and can be fabricated by low-cost roll-to-roll process. Here, we systematically investigated the interrelations between photovoltaic properties and the domain morphology of the active layer in OSCs based on films of poly-(9,9-dioctylfluorene-co-bithiophene) (F8T2)/[6,6]-phenyl C71-butyric acid methyl ester (PC71BM) blend annealed at various temperatures (Tan). The scanning transmission X-ray microscopy (STXM) revealed that fullerene mixing (ΦFullerene) in the polymer matrix decreases with increase in Tan while the domain size (L) is nearly independent of Tan. The TEM-S mapping image suggests that the polymer matrix consist of polymer clusters of several nm and fullerene. We found that the charge formation efficiency (ΦCF), internal quantum efficiency (ΦIQ), and power conversion efficiency (PCE) are dominantly determined by ΦFullerene. We interpreted these observations in terms of the polymer clusters within the polymer matrix