Hydrogen/Deuterium Exchange Reaction Rate of Cytochrome Determined by Droplet Collision Atmospheric Pressure Infrared Laser Ablation Mass Spectrometry.

The hydrogen/deuterium (H/D) exchange rate is an optimal measure for studying the structures and dynamics of hydrogen bonding systems, as it reflects the molecular contact environment and the strength of the hydrogen bonds. A method for rapid measurement of the H/D exchange reaction rates is required to examine the intermolecular environments of molecules in solutions. We developed a droplet collision atmospheric pressure infrared laser ablation mass spectrometry technique for this purpose.

Interlaboratory comparison of electron paramagnetic resonance tooth enamel dosimetry with investigations of the dose responses of the standard samples.

A total of seven Japanese laboratories participated in an intercomparison study to estimate the dose given to tooth enamel samples, using the electron spin resonance method. Each of four of the participating laboratories prepared a set of tooth enamel samples, using the electron spin resonance method. Four of the participating laboratories each prepared a set of tooth enamel samples, consisting of seven standard aliquots irradiated from 100 to 2000 mGy and three samples with an 'unknown' dose between 140 and 960 mGy, were intended to eliminate bias from sample preparation.

Estimation of external dose for wild Japanese macaques captured in Fukushima prefecture: decomposition of electron spin resonance spectrum.

The signal intensities of CO2- radicals in teeth can be utilised as an individual indicator of the cumulative external dose for animals. To accurately determine the external dose, it is desirable to analyse the CO2- radical intensity and improve its detection limit. We recently reported a dose-response in the range of 0-200 mGy and estimated the absorbed dose for seven wild Japanese macaques captured in/around the related areas to the Fukushima Daiichi Nuclear Power Plant accident.

Ultraviolet photodissociation of Mg-NO complex: Ion imaging of a reaction branching in the excited states.

Ultraviolet photodissociation processes of gas phase Mg-NO complex were studied by photofragment ion imaging experiments and theoretical calculations for excited electronic states. At 355 nm excitation, both Mg and NO photofragment ions were observed with positive anisotropy parameters, and theoretical calculations revealed that the two dissociation channels originate from an electronic transition from a bonding orbital consisting of Mg 3s and NO π* orbitals to an antibonding counterpart. For the NO channel, the photofragment image exhibited a high anisotropy (β = 1.

Roles of resonant muonic molecule in new kinetics model and muon catalyzed fusion in compressed gas.

Muon catalyzed fusion ([Formula: see text]CF) in which an elementary particle, muon, facilitates the nuclear fusion between the hydrogen isotopes has been investigated in a long history. In contrast to the rich theoretical and experimental information on the [Formula: see text]CF in cold targets, there is relatively scarce information on the high temperature gas targets of deuterium-tritium mixture with high-thermal efficiency. We demonstrate new kinetics model of [Formula: see text]CF including three roles of resonant muonic molecules, (i) changing isotopic population, (ii) producing epi-thermal muonic atoms, and (iii) inducing fusion in-flight.

Photodissociation processes of a water-oxygen complex cation studied by an ion imaging technique.

Photochemistry of molecular complex ions in the atmosphere affects the composition, density, and growth of chemical species. Photodissociation processes of a mass-selected O(HO) complex ion in the visible and ultraviolet regions were studied by ion imaging experiments and theoretical calculations. At 473 nm excitation, O was the predominant photofragment ion produced.

Visible photodissociation of the CO dimer cation: fast and slow dissociation dynamics in the excited state.

Velocity and angular distributions of photofragment CO2+ ions produced from mass-selected (CO2)2+ at 532 nm excitation were observed in an ion imaging experiment. The velocity distribution was assigned to two components, fast and slow velocity components, which was consistent with the previous study by Bowers et al. The anisotropy parameters of the angular distributions for the fast and slow velocity components were experimentally determined to be βfast = 1.

Ion Imaging of MgI Photofragment in Ultraviolet Photodissociation of Mass-Selected MgICH Complex.

We have observed images of MgI fragment ions produced in ultraviolet laser photodissociation of mass-selected MgICH ions at 266 nm. Split distribution almost perpendicular to the polarization direction of the photolysis laser was observed in the photofragment image. Potential energy curves of MgICH were obtained by theoretical calculations.

Development of a linear-type double reflectron for focused imaging of photofragment ions from mass-selected complex ions.

An ion imaging apparatus with a double linear reflectron mass spectrometer has been developed, in order to measure velocity and angular distributions of mass-analyzed fragment ions produced by photodissociation of mass-selected gas phase complex ions. The 1st and the 2nd linear reflectrons were placed facing each other and controlled by high-voltage pulses in order to perform the mass-separation of precursor ions in the 1st reflectron and to observe the focused image of the photofragment ions in the 2nd reflectron. For this purpose, metal meshes were attached on all electrodes in the 1st reflectron, whereas the mesh was attached only on the last electrode in the 2nd reflectron.

Photofragment ion imaging from mass-selected MgBrCH complex: Dissociation mechanism following photoinduced charge transfer.

We have observed fragment ion images produced by ultraviolet photodissociation of MgBrCH complex ions using a reflectron time-of-flight mass spectrometer combined with an imaging detector. The BrCH fragment ion was produced after the 266-nm excitation of MgBrCH. In the image of the BrCH ions, a split distribution was observed parallel to the polarization direction of the photolysis laser.