A5066798645- Advanced Chemical Physics Studies
- Atomic and Molecular Physics
- Marine and coastal ecosystems
- Soil and Water Nutrient Dynamics
- Mass Spectrometry Techniques and Applications
- Aquatic Ecosystems and Phytoplankton Dynamics
- X-ray Spectroscopy and Fluorescence Analysis
- Water Quality and Pollution Assessment
- Oceanographic and Atmospheric Processes
- Coastal and Marine Dynamics
- Nuclear physics research studies
- Atmospheric Ozone and Climate
- Electron and X-Ray Spectroscopy Techniques
- Photochemistry and Electron Transfer Studies
- Hydrological Forecasting Using AI
- Fish Ecology and Management Studies
- Rare-earth and actinide compounds
- Geology and Paleoclimatology Research
- Spectroscopy and Laser Applications
- Laser-Matter Interactions and Applications
- Isotope Analysis in Ecology
- Ion-surface interactions and analysis
- Groundwater and Isotope Geochemistry
- Aquatic Invertebrate Ecology and Behavior
- Spectroscopy and Quantum Chemical Studies
Kasumigaura Medical Center
2016-2025
Tohoku University
2010-2016
We report the first observation of electron-transfer-mediated decay (ETMD) and interatomic Coulombic (ICD) from triply charged states with an inner-valence vacancy, using Ar dimer as example. These ETMD ICD processes, which lead to fragmentation Ar(3+)-Ar into Ar(2+)-Ar(2+) Ar(3+)-Ar+, respectively, are unambiguously identified by electron-ion-ion coincidence spectroscopy in kinetic energy or electron release between two fragment ions measured coincidence.
The first experimental evidence of rotational Doppler broadening in photoelectron spectra, reported here, show good agreement with recently described theoretical predictions. dependence the on temperature and kinetic energy is quantitatively predicted by theory. experiments verify that contributions to linewidth are comparable those from translational must be considered analysis high-resolution spectra. A classical model accounting for this newly observed effect presented.
We report the first evidence for double-slit interferences in a polyatomic molecule, which we have observed experimental carbon 1s photoelectron spectra of acetylene (or ethyne). The been measured over photon energy range 310–930 eV and show prominent oscillations intensity ratios σg(υ)/σu(υ) vibrational quantum numbers υ = 0,1 σs(υ 1)/σs(υ 0) symmetry s g,u. findings are very good agreement with ab initio density functional theory (DFT) calculations compatible Cohen–Fano mechanism coherent...
Abstract This study presents results of circulation and residence time in lakes influenced by wind‐induced mixing investigated with numerical simulations. The area is Lake Kasumigaura, a continuous lake system primally consisting two lakes, West North Lake. Although metrological conditions depths are similar for both the surface shape very different. A model resolves primary features wind‐driven forced observed river discharges wind stress. passive tracer released from mouths used to...
Using momentum-resolved electron-ion multicoincidence spectroscopy, we have investigated interatomic Coulombic decay (ICD) in the heteronuclear NeAr dimer following Ne $1s$ Auger decay. The measured intensity ratio for three ICD transitions Ne${}^{2+}$($2{s}^{\ensuremath{-}1}2{p}^{\ensuremath{-}1} {}^{1}P$)Ar to Ne${}^{2+}$($2{p}^{\ensuremath{-}2} {}^{1}S$)--Ar${}^{+}$($3{p}^{\ensuremath{-}1}$), {}^{1}D$)-Ar${}^{+}$($3{p}^{\ensuremath{-}1}$), and {}^{3}P$)Ar...
We have unambiguously identified interatomic Coulombic decay in NeAr from the inner-valence double-vacancy state Ne-Ar(2+)(3s(-2)) to outer-valence triple-vacancy states Ne(+)(2p(-1))-Ar(2+)(3p(-2)) by momentum-resolved electron-ion multicoincidence. This is first observation of where three electrons (3e) participate. The results suggest that this 3e significantly faster than other competing processes like fluorescence and charge transfer via curve crossing.
Recoil-induced rotational excitation accompanying photoionization has been measured for the X, A, and B states of N(2)(+) CO(+) over a range photon energies from 60 to 900 eV. The mean recoil increases linearly with kinetic energy photoelectron, slopes ranging 0.73×10(-5) 1.40×10(-5). These are generally (but not completely) in accord simple model that treats electrons as if they were emitted isolated atoms. This treatment takes into account atom which electron is emitted, molecular-frame...
Spectator resonant KL23L23 Auger electron spectra have been measured in the Si 1s photoexcitation region of Si(CH3)4 using monochromatized undulator radiation combined with a hemispherical spectrometer. The broad peak high intensity total ion yield spectrum, coming mainly from excitation into 6t2 vacant orbital, induces spectator decay which excited remains its orbital. component on higher energy side this through Rydberg orbital produces decays moves slightly or is partly shaken up to...
Spectator resonant Auger-electron spectra have been measured in the Si $1s$ photoexcitation region of SiF${}_{4}$ using an electron spectroscopic technique combined with undulator radiation. A transition highest intensity total ion yield spectrum, which comes from excitation a into $6{t}_{2}$ valence orbital, generates Auger decays excited remains predominantly orbital or is partly shaken up high-lying Rydberg orbital. The higher-lying peak generated through orbitals induces to down...
In this study, the relationships between concentration and isotopic compositions (δ15NNO3 δ18ONO3) of nitrate in river water land use topographic characteristics watershed were analyzed for tributaries two major inflow rivers (Hokota River Tomoe River) Lake Kitaura (Ibaraki Prefecture, Japan). Modelling by Random Forests machine learning algorithm combination with statistical analyses (correlation analysis principal component analysis) revealed that crop farming dry fields (i.e., application...
We have investigated charge separation Ne+-Ne+ and Ne2+-Ne+ from Ne2 after direct double photoionization compared them with those 1s followed by KLL Auger decay also 2p of Ar2 LMM decay. The takes place via radiative transfer one-site two-hole states Ne2+(2p4)-Ne, whereas the interatomic Coulombic Ne2+(2s12p5)-Ne.
X-ray photo-absorption (XA) spectra of SiF4 and Si(CH3)4 have been measured in the Si K-shell transition region using monochromatized undulator radiation theoretical calculations performed within framework density functional theory. For main peak structures XA spectrum reproduced well with calculation. Further we theoretically simulated a small Si:1s→6a1 excitation, by sampling distorted geometries classical trajectory at ground state, which is forbidden under dipole selection rule. only one...
Excessive loadings of terrestrial nitrogen and phosphorus, as well their imbalances with silicon, have been recognized one the major causes water quality ecosystem deterioration in receiving waters. In this study, a periodic monitoring was conducted rivers streams tropical island (Ishigaki Island, Japan) to identify factors controlling concentrations dissolved inorganic (DIN), total phosphorus (TP) silicon (DSi) special focus on catchment characteristics (e.g., land use, surface geology,...
Cascade Si LVV Auger decays following KL(23)L(23) transitions have been measured in SiF(4) molecule using an electron spectrometer combined with monochromatized undulator radiation. Molecular cascade processes from the two 2p holes states largely generate wide band structures spectra due to sequential emission leading multiple valence holes. However, a peak high yield is observed for first time at about 103 eV, energy being considerably higher than energies of normal electron, instance...
Abstract Cyanobacterial blooms in lakes cause serious environmental problems on a global scale. Planktothrix (a filamentous cyanobacterium) occurred during winter and spring from 2007 to 2011 Lake Kasumigaura, eutrophic lake located Japan. This study analysed water quality the period of abundance (2007–2010) at centre Kasumigaura compared it that succeeding period, which did not have (2012–2015). The average phytoplankton biovolume was larger than would contribute high chemical oxygen demand...
北浦の底層水や底泥の酸素消費速度を調査するとともに, 現場で観測された水温成層や貧酸素水塊に関するデータを用いて, 北浦の貧酸素水塊の形成要因となる底層水と底泥の酸素消費の寄与について検討した。北浦の底層水の酸素消費速度は2,550~2,910 mg m-3 d-1, 底泥の酸素消費速度は652~1,080 m-2 d-1であった。水温成層を形成した時の底層水の水柱の高さが0.16 m未満では底泥の酸素消費の寄与が大きくなり, 0.60 mを越えると底層水の酸素消費の寄与が大きくなることが示唆された。また, 2019年7月28日から8月3日にかけて北浦の釜谷沖水質自動監視所における水温成層や貧酸素水塊の鉛直時系列データを用いて酸素消費の寄与を検討したところ, 湖底から水温躍層内全体では底層水の酸素消費の寄与が大きいが, 貧酸素水塊は湖底から形成されていたため, 底泥の酸素消費の影響も無視できないと考えられた。
Abstract Seasonal stratification hinders the ventilation of hypolimnion water, leading to formation an anaerobic benthic layer in shallow lakes. This study quantifies processes hypoxia and recovery Lake Kasumigaura, Japan, under conditions developing metalimnion during early summer, specifically from May mid-July 2022. We conducted direct observations vertical turbulent fluxes dissolved oxygen (DO), as well heat momentum using eddy-covariance system (ECS), enabling simultaneous measurements...
湖沼水質に対する植物プランクトンの影響を検討するためには,植物プランクトンを体積で評価することが必要であるが,植物プランクトン体積の算出には多くの労力と高い専門性が必要であり,多地点・高頻度での測定は難しい.そこで本研究では,簡便に植物プランクトン体積を算出することを目的とし,霞ヶ浦における各植物プランクトンの細胞体積を整理し,その利用可能性について検討した.整理した各細胞体積を,2005年度から測定された毎月の細胞数データに乗じて,植物プランクトン体積の変動を算出し,既往研究の実測値と比較した.計算された総体積は,実測値と有意な正の相関を示し,総体積に占める各分類群合計体積の割合も,主だった綱で正の相関を示した.このことから,細胞数に一定値を乗ずる方法は有効であることが示唆された.細胞数のみならず体積で植物プランクトン群集を理解することによって,水質や生態系に対する影響をより具体的に検討できることが期待できる.
The large shallow lake complex of Lake Kasumigaura comprises three water bodies: Nishiura, Kitaura, and Sotonasakaura, which are connected by rivers.The community structure biovolume phytoplankton important factors for the ecology quality lake.However, few studies have been conducted recently on communities entire Kasumigaura.The aim this study was to clarify changes in from 2005 2019 results showed that dominant taxa were Bacillariophyceae 2007, Planktothrix (Oscillatoriales, Cyanophyceae)...