Ion Energy Transfer Research Articles

Ion species discrimination method by linear energy transfer measurement in Fujifilm BAS-SR imaging plate.

We have developed a novel discrimination methodology to identify ions in multispecies beams with similar charge-to-mass ratios, but different atomic numbers. After an initial separation by charge-to-mass ratios using co-linear electric and magnetic fields, individual ions can be discriminated by considering the linear energy transfer of ions irradiating a stimulable phosphor plate (Fujifilm imaging plate) by comparison with the Monte Carlo calculation. We apply the method to energetic multispecies laser-driven ion beams and use it to identify silver ions produced by the interaction between a high contrast, high intensity laser pulse; and a sub-micrometer silver foil target. We also show that this method can be used to calibrate the imaging plate for arbitrary ion species in the range of Z ≥ 6 with dE/dx > 0.1 MeV/μm without requiring individual calibration.

2.3- and 4.4-μm Lasing in Cr, Fe:Zn1 –xMnxSe (x = 0.3) Single Crystal Pumped by Q-Switched Er:YLF Laser at 1.73 μm

Novel Cr2+ and Fe2+ co-doped Zn1–xMnxSe (x = 0.3) crystal with Cr2+ to Fe2+ ions concentration ratio of about 1 : 2 (both doping ions concentration were at the ~1018 cm–3 level) with a good optical quality was synthesized. Under pumping by a Q-switched Er:YLF laser at 1.73 μm, the oscillations of Cr2+ ions at 2.3 μm as well as Fe2+ ions at 4.4 μm were realized. Both regimes, i.e. intracavity pumping of Fe2+ ions by Cr2+ ions as well as excitation through the Cr2+ → Fe2+ ions energy transfer mechanism, were demonstrated. The output energy for Cr2+ ions lasing at 2.3 μm was up to 900 μJ while Fe2+ ions lasing at 4.4 μm reached up to 60 μJ in the intracavity pumping mode. In the Cr2+ → Fe2+ energy transfer mode, the maximum output energy was 20 μJ at 4.4 μm. Laser generation at 2.3 μm was observed up to 340 K while Fe2+ ions oscillations stopped for temperatures above ~150 K. The Fe2+ ions oscillation wavelength was observed to shift with temperature increase from ~4.4 μm at 78 K to ~4.5 μm at 150 K. The Fe2+ ions output pulses were quite stable in amplitude and temporal domain in both excitation modes with beam profile close to the fundamental transversal mode.

Chemical Dosimetry in the “Water Window”: Ferric Ions and Hydroxyl Radicals Produced by Intense Soft X Rays

A standard Fricke dosimeter was used to measure the absorbed dose via the oxidation yields of Fe3+ ions in an aqueous environment induced by soft X rays within the "water window" spectral range. We also exploited the property of a neutral solution containing terephthalic acid as a tool for selective detection of OH radicals. Both dosimetric systems were irradiated using the experimental pulsed laser-plasma soft X-ray source as well as conventional 1.25-MeV gamma rays. Radiation chemical yields of Fe3+ ions and OH radicals were determined to be (5.13 ± 0.94) × 10-1 µmol·J-1 (4.95 ± 0.91 100eV-1) and (2.33 ± 0.35) × 10-2 µmol·J-1 (0.23 ± 0.03 100eV-1), respectively. Measurements were supported by Monte Carlo simulations to estimate the linear energy transfer of the water window radiation. The simulation results are in good agreement with expected linear energy transfer of ions inducing the same Fe3+ ion and OH radical radiation chemical yield.

Mid-IR lasing of Fe2+ ions via Cr2+ → Fe2+ energy transfer process with YLF:Er or laser diode pumping at 1.7 µm

A nonradiative Cr2+ → Fe2+ ions energy transfer process in Zn1-xMnxSe:Cr2+,Fe2+ (x = 0.05) single crystal with a Cr2+ to Fe2+ ions concentration ratio about 2.5:1 was investigated under short-pulse (200 ns) ∼1.73 µm excitation by YLF:Er laser. Fe2+ ions lasing in a temperature range from 78 K up to 200 K was achieved and the central oscillation wavelength was observed to increase from 4.1 µm to 4.4 µm, depending on the temperature of the active medium. Moreover, stable Fe2+ ions lasing under a “long” pulse excitation (1 ms, 10 Hz) by a ∼1.71 µm laser diode were demonstrated. The laser generated in a temperature range from 78 K up to 110 K at a central wavelength around ∼4.17 µm. The maximum mean laser output power of 4.1 mW with a slope efficiency of 2.3% with respect to the absorbed power was achieved. These results present a new possibility to develop a simple and compact diode-pumped coherent mid-infrared (4.1–4.3 µm) laser sources.

SOI Thin Microdosimeters for High LET Single-Event Upset Studies in Fe, O, Xe, and Cocktail Ion Beam Fields

The response of a 5- <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu \text{m}$ </tex-math></inline-formula> -thin silicon on insulator (SOI) 3-D microdosimeter was investigated for single-event upset applications by measuring the linear energy transfer (LET) of different high LET ions. The charge collection characteristics of the device were performed using the ion beam-induced charge collection (IBIC) technique with 3- and 5.5-MeV He <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2+</sup> ions incident on the microdosimeter. The microdosimeter was irradiated with <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">16</sup> O, <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">56</sup> Fe, and <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">124</sup> Xe ions and was able to determine the LET within 5% for most configurations apart from <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">124</sup> Xe. It was observed that on average, measured LET was 12% lower for 30-MeV/u <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">124</sup> Xe ion traversing through different thickness Kapton absorbers in comparison to Geant4 simulations. This discrepancy can be partly attributed to uncertainties in the thickness of the energy degraders and the thickness of the SOI layer of the devices. The effects of overlayer thickness variation are not easily observed for ions with much lower LET as O and Fe. Based on that, it is difficult to make conclusion that the plasma effect is observed for 30-MeV/u <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">124</sup> Xe ions and further research to be carried out for ion with LET higher than 12 MeV/ <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu \text{m}$ </tex-math></inline-formula> .

Fine tuning of polymer content for enhanced structure and luminescent properties of Eu3+:siloxane–poly(methyl methacrylate) hybrids to be applied in photonics

The increasing demand for multifunctional materials for use in several application fields has been encouraging research into luminescent hybrid materials. These have the advantage of combining features of both organic and inorganic matter, which can be tailored to enhance emission conditions. This work aims to elucidate structural/luminescence relations of Eu3+:siloxane–poly(methyl methacrylate) hybrid materials. Polymer content was evaluated through characterization of samples with increasing polymer/Si molar ratios. Results showed that the sample with the highest amount of polymer in its composition, PMMA8, had optimized emission features on account of the larger number of carbonyl groups available for Eu3+ coordination. This enhancement is evidenced by the quantum efficiency (q) and lifetime (τexp) values, which were considerably higher (q = 24.7% and τexp = 0.62 ms) for PMMA8 hybrid than for the other samples. Thus, the hydrophobic polymer reduced the interaction of dopant ions to hydroxyl quenching groups and led to better dispersion, minimizing ion–ion energy transfer.

Crystal structure, vibrational and optic properties of 2-N-methylamino-3-methylpyridine N-oxide – Its X-ray and spectroscopic studies as well as DFT quantum chemical calculations

The crystal and molecular structure and physicochemical properties of 2-N-methylamino-3-methylpyridine N-oxide (MA3MPO) have been studied. MA3MPO was synthesized from 2-amino-3-methylpyridine by several steps to form colorless crystals suitable for crystallographic analysis. The data reveal that MA3MPO crystallizes in the monoclinic space group P21/n. The studied compound contains a nearly flat triply substituted pyridine skeleton whose structure is stabilized by an intramolecular N–H⋅⋅⋅O hydrogen bond. The N-oxide molecules are connected together by weak C–H⋯O hydrogen bonds, an acceptor of which is the oxygen atom from the N-oxide group. This leads to creation of two-dimensional network of hydrogen bonds. Its IR, Raman, UV–Vis and luminescence spectra have been measured and analyzed on the basis of DFT and NBO quantum chemical calculations in which the B3LYP/6-311++G(d,p) approach was applied. The distribution of the electron levels in the studied compound has been analyzed in terms of the possibility of its participation in the ligand-to-lanthanide ion energy transfer.

Mid-IR (44 μm) Zn1−xMnxSe:Cr2+,Fe2+ (x = 03) laser pumped by 17 μm laser using Cr2+-Fe2+ energy transfer

This Letter determines the Cr2+-Fe2+ ions energy transfer process parameters in the Zn1−xMnxSe:Cr2+,Fe2+ (x=0.3) crystal and demonstrates a dipole-dipole type of the Cr2+-Fe2+ ions nonradiative energy transfer. The intracavity Cr2+-Fe2+ pumping as well as pumping through Cr2+-Fe2+ energy transfer in the Zn1−xMnxSe:Cr2+, Fe2+ (x=0.3) crystal under 1735 nm excitation by an YLF:Er laser was realized in a temperature range of 78 up to 150 K for the first time, to the best of our knowledge. Output pulse energy up to 20 μJ at ∼4400 nm under 5.5 mJ of 1735 nm absorbed pump energy was obtained for the Cr2+-Fe2+ ions energy transfer mode.

Energy Transfer of Peptide Ions Colliding with a Self‐Assembled Monolayer Surface. The Influence of Peptide Ion Size

Summary of main observation and conclusionAtomistic dynamics of protonated polyglycine, glyn‐H+ (n = 3, 5, and 7), colliding with a fluorinated octanethiol self‐assembled monolayer (F‐SAM) surface has been studied by trajectory calculations. The effects of peptide size on the collision processes and energy transfer efficiencies are emphasized and discussed in detail. The simulations show that the fraction of trapping, which is related to the soft‐landing process, dramatically drops with the increase in collision energy, but gently increases with the peptide size. The average energy transfer to the peptide ion's internal degrees of freedom, ΔEint, is compared with previous experiments. The limiting probability Po of energy transfer to the surface is given by fitting a function of Poexp(–b/Ei). Our results suggest that the efficiencies of energy transfer are less dependent on the masses, even the categories of the peptide ions, and are determined by the character of the surfaces.

Color-Tunable Upconversion in Er3+/Yb3+-Codoped KLaF4 Nanophosphors by Incorporation of Tm3+ Ions for Biological Applications.

Heavily doped nanocrystals of host KLaF4 with rare earth (RE3+ = Er3+, Tm3+, and Yb3+) ions prepared by a simple one-step template-free wet-chemical route have been reported. Prepared KLaF4 nanocrystals reveal phase-pure cubic structures (lattice constant a = 5.931Å) with space group Fm3m. Precisely defined molar ratios of heavily dopant RE3+ ions allow us to achieve wide color upconversion (UC) emission tunability (blue, green to yellow–orange–red) and white light, without any morphology and structure changes. The enhanced red emission by a factor of ∼120 has been achieved in 20% Yb3+ and 5% Tm3+ ions in KLaF4:1% Er3+ nanocrystals, which is due to an efficient sensitizer–acceptor (Yb3+ to Er3+ and Tm3+ ions) energy transfer and interexchange energy process between acceptors. For the first time, the key role of sensitizer (Yb3+) for UC emission energy transfer to Er3+ and/or Tm3+ is experimentally demonstrated. The evidence of upconversion photoluminescence excitation spectra reveals a broad safe biological excitation window (690–1040 nm), which can be well demonstrated by low-cost NIR diode lasers/LEDs. The applicability of these cubic nanophosphors is demonstrated as light-emitting polymer composite coatings and blocks for LEDs and solar cell panels. These well-dispersed UC nanocrystals can also be found to have greater use in bioimaging and spectral studies.

Collisional Ion Energy Transfer Model for Understanding Wrinkles on Poly (dimethylsiloxane) Surfaces after Oxygen Ion Beam Irradiations

Collisional Ion Energy Transfer Model for Understanding Wrinkles on Poly (dimethylsiloxane) Surfaces after Oxygen Ion Beam Irradiations

Theoretical insight in highly luminescent properties of Eu(III) complex with phenanthroline

The complete photophysical process, from absorption in the UV region, excited state energy transitions, ligand → Eu(III) energy transfer to luminescence of Eu(phen)2(NO3)3 in Vis region, is elucidated by means of two theoretical approaches and in close relation to the experiment. The energy diagram, S1 and T1 excited state character and the concurrent energy transitions in phen and its Eu(III) complex in gas phase and in DMF solution are predicted by DFT-TDDFT/PBE1PBE calculations. The contributions of phen and NO3 ligands to the excited state energies are evaluated in detail. The high population of T1 state (due to effective intersystem crossing) and its closeness in energy to the 5D0 level of the Eu(III) (0.4 eV), make T1 state the key donor for the excited state ligand-to-metal ion energy transfer. The T1 state energy of phen chromophore determines this one in its Eu(III) and Gd(III) complexes. The solvent DMF effect on the lowest triplet excited state is insignificant. Providing similar accuracy for the vertical excited state energy as the estimates for the TDDFT/PBE1PBE energy of T1 minimum and the experimental phosphorescence data, INDO/S-CIS method could be reliably used for further prediction of the luminescent properties. A computational strategy based on Sparkle/RM1 geometry, INDO/S-CIS excitation energies, Judd-Ofelt parameters, obtained with the QDC model and energy transfer rates predicted T1 → 5D0 as the most probable channel of the energy transfer process and luminescent quantum yield of 32% close to the experimental result of 35%.

Synthesis, Photoluminescence Behavior of Green Light Emitting Tb(III) Complexes and Mechanistic Investigation of Energy Transfer Process.

A series of five new terbium(III) ion complexes with 4,4-difluoro-1-phenylbutane-1,3-dione (HDPBD) and anciliary ligands was synthesized. The composition and properties of complexes were analyzed by elemental analysis, IR, NMR, powder X-ray diffaraction, TG-DTG and photoluminescence spectroscopy. These complexes exhibited ligand sensitized green emission at 546nm associated with 5D4 → 7F5 transitions of terbium ion in the emission spectra. The photoluminescence study manifested that the organic ligands act as antenna and facilitate the absorbed energy to emitting levels of Tb(III) ion efficiently. The enhanced luminescence intensity and decay time of ternary C2-C5 complexes observed due to synergistic effect of anciliary ligands. The CIE color coordinates of complexes came under the green region of chromaticity diagram. The mechanistic investigation of intramolecular energy transfer in the complexes was discussed in detail. These terbium(III) complexes can be thrivingly used as one of the green component in light emitting material and in display devices. Graphical Abstract Illustrate the sensitization process of the Tb ion and intramolecular energy transfer process in the Tb3+ complex.

Efficiency improvement of up–conversion luminescence of Yb3+/Tm3+ co-doped tellurite glass microsphere

Three potential techniques, i.e. the optical taper fiber–microsphere device(OFMD), employment of the low phonon energy tellurite glass and the optimal concentration of rare-earth ions are investigated and identified for improving the efficiency of up-conversion (UC) luminescence for rare-earth ion doped materials excited by laser. The tellurite glass with composition of 77TeO2–12Na2O–5ZnO–5La2O3 was synthesized with different Yb3+/Tm3+co-doped concentration. The OFMD with high efficiency coupling and high energy density whispering gallery mode (WGM) was constructed. By the excitation of 976 nm laser, the WGM resonance enhancement UC blue (475 nm) and red (648 nm) light were obtained. The WGM resonance enhancement UC luminescence mechanism, the rare-earth ions energy transfer mechanism and the optimal Tm3+ concentration were investigated.

Luminescent Eu3+–dibenzoylmethanate complex with sulfoxide ligand as sensitizer applied to organic light- emitting diodes

In this work the synthesis, characterization and photoluminescent and electroluminescent behavior of the [Eu(DBM)₃(PTSO)₂] complex have been investigated. The emission spectrum of this Eu³⁺–β– diketonate complex show characteristics narrow bands arising from the ⁵D₀→⁷Fȷ (J = 0–4) transitions, which are split according to the selection rule for Cs, Cn or Cnv site symmetries. Triple and doublelayer organic light-emitting diodes (OLEDs) using NPB as hole transporting layer, Alq₃ as electron transporting layer and [Eu(DBM)₃(PTSO)₂] complex as emitting and electron transporting layer were grown and characterized. We found the presence of two concurrent mechanisms for the electroluminescent behavior: (1) the electroluminescence (EL) from the exciton-ligand-Eu³+ ion energy transfer, responsible for the EL narrow bands; and (2) the molecular electrophosphorescence with an initial energy transfer exciton-ligand and posterior intersystem crossing from the excited singlet S₁ to the triplet T state followed by molecular phosphorescence (T→S₀). The electroluminescent behavior of [Eu(DBM)₃(PTSO)₂] complex suggest that this complex is promising to applied at Light Conversion Molecular Devices (LCMDs) such as in OLED devices.

Soft errors in 10-nm-scale magnetic tunnel junctions exposed to high-energy heavy-ion radiation

The influences of various types of high-energy heavy-ion radiation on 10-nm-scale CoFeB–MgO magnetic tunnel junctions with a perpendicular easy axis have been investigated. In addition to possible latent damage, which has already been pointed out in previous studies, high-energy heavy-ion bombardments demonstrated that the magnetic tunnel junctions may exhibit clear flips between their high- and low-resistance states designed for a digital bit 1 or 0. It was also demonstrated that flipped magnetic tunnel junctions still may provide proper memory functions such as read, write, and hold capabilities. These two findings proved that high-energy heavy ions can produce recoverable bit flips in magnetic tunnel junctions, i.e., soft errors. Data analyses suggested that the resistance flips stem from magnetization reversals of the ferromagnetic layers and that each of them is caused by a single strike of heavy ions. It was concurrently found that an ion strike does not always result in a flip, suggesting a stochastic process behind the flip. Experimental data also showed that the flip phenomenon is dependent on the device and heavy-ion characteristics. Among them, the diameter of the device and the linear energy transfer of the heavy ions were revealed as the key parameters. From their dependences, the physical mechanism behind the flip was discussed. It is likely that a 10-nm-scale ferromagnetic disk loses its magnetization due to a local temperature increase induced by a single strike of heavy ions; this demagnetization is followed by a cooling period associated with a possible stochastic recovery process. On the basis of this hypothesis, a simple analytical model was developed, and it was found that the model accounts for the results reasonably well. This model also predicted that magnetic tunnel junctions provide sufficiently high soft-error reliability for use in space, highlighting their advantage over their counterpart conventional semiconductor memories.

A comprehensive model of Penning energy transfers in Ar − CO2 mixtures

Ionizing energy transfer mechanisms due to the excited argon atoms, called Penning transfers, have been investigated for various Ar − CO2 mixtures at 0.4, 0.8, 1.2 and 1.8 atm gas pressures. The Penning energy transfer probabilities are extracted from the systematic gas gain measurements carried out in cylindrical proportional counters. In this report, contributions of the several transfer processes are identified by studying the pressure and mixing proportion dependence of the transfer rates with a model.

Visualization of 1.908-μm radiation of a Tm:YLF laser using PbF2-based ceramics doped with Ho3+ ions

Visualization of IR radiation of a Tm:YLF laser at 1908 nm in PbF2 ceramic samples has been investigated. Luminescence spectra of the PbF2 samples doped with Нo3+ exhibited bands at wavelengths of 490, 545, and 650 nm (this red band is the strongest). It is established that at, a low laser intensity, the 5I5 and 5I6 levels are occupied mainly due to the ion–ion energy transfer.

Tunable luminescence and energy transfer properties in YVO4:Bi3+, Eu3+ phosphors

In this paper, YVO4:Bi3+, Eu3+ phosphors have been synthesized by high-temperature solid-state method. The samples were characterized by X-ray powder diffraction, photoluminescence spectra, luminescence lifetime, and GSAS structure refinement. The excitation spectrum of YVO4:Bi3+, Eu3+ monitoring at 622 nm was a broad band with major peak located at 280 nm. It contained the charge transfer from 2p orbit of O2− to 4f orbit of Eu3+ (257 nm) and the absorbing from energy level transition of Bi3+ (1S0→3P1, 346 nm) and VO4 3− (lA1→1T2, 286 nm and lA1→1T1, 320 nm) through gauss fitting. Upon excitation at a wavelength of 280 nm, the major emission peak of YVO4:Bi3+, Eu3+ located at 622 nm (red) was attributed to the electric dipole transition 5D0→7F2 of Eu3+. The energy transfer mechanism of Bi3+→Eu3+ was also studied to be dipole–quadrupole mechanism of electric multipole interaction, and the critical distance between Eu3+ and Bi3+ was calculated by concentration quenching method. The emission color of YVO4:Bi3+, Eu3+ can be tuned by the energy transfer of ions and the concentration of activator. In a word, the material has a good application prospects in the field of light-emitting diode under ultraviolet excitation.

Ag7+ ion induced modification of morphology, optical and luminescence behaviour of charge compensated CaMoO4 nanophosphor

The present paper reports on the swift heavy ion (SHI) induced structural, optical and luminescence properties of CaMoO4:Dy3+/K+ nanophosphor synthesized via hydrothermal route. Herein 100MeV Ag7+ ion beam was used varying fluence from 1×1011 to 1×1013ions/cm2. The depth profile of the Ag7+ ions was estimated using SRIM code. XRD and FESEM results revealed the loss of crystallinity and reduction in particle size after SHI irradiations. The XPS technique confirmed the stability of oxidation states of the elements. Reflectance spectra exhibited a red shift in the absorption band, followed by a decrease in band gap. Decrease in the intensity of the photoluminescence peaks without any change in band positions was also obtained after ion irradiation. The thermoluminescence (TL) characteristics were discussed in detail, and the trapping parameter was calculated. The results were compared on the grounds of linear energy transfer of the irradiated ions.