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A Wien filter was designed for and tested with a room temperature electron beam ion source (EBIS). Xenon charge state spectra up to the charge state Xe46+ were resolved as well as the isotopes of krypton using apertures of different sizes. The complete setup consisting of an EBIS and a Wien filter has a length of less than 1 m substituting a complete classical beamline setup. The Wien filter is equipped with removable permanent magnets. Hence total beam current measurements are possible via simple removal of the permanent magnets. In dependence on the needs of resolution a weak (0.2 T) or a strong (0.5 T) magnets setup can be used. In this paper the principle of operation and the design of the Wien filter meeting the requirements of an EBIS are briefly discussed. The first ion beam extraction and separation experiments with a Dresden EBIS are presented.

Photo- and thermoluminescence (TL) spectra of NaLaF4:Ln3+ (Ln=Ce,Pr,Nd,Sm,Eu,Gd,Tb,Dy,Ho,Er,Tm) and NaLaF4:Ce3+, Ln3+ (Ln=Nd,Sm,Ho,Er,Tm) are presented and used together with the empirical Dorenbos model in order to establish the 4f energy level positions of all tri- and divalent lanthanide ions doped in NaLaF4. The information will be presented in the form of an energy level diagram. It is shown that in addition to this diagram only two assumptions, viz., the presence of two host related electron traps and the presence of Vk-centers, are necessary for explaining the lanthanide-specific TL glow curves of both Ln mono- and Ce–Ln codoped NaLaF4. [ABSTRACT FROM AUTHOR]

Infrared multiple photon dissociation spectra for size-selected water cluster anions (H2O)n-, n=15–50, are presented covering the frequency range of 560–1820 cm-1. The cluster ions are trapped and cooled by collisions with ambient He gas at 20 K, with the goal of defining the cluster temperature better than in previous investigations of these species. Signal is seen in two frequency regions centered around 700 and 1500–1650 cm-1, corresponding to water librational and bending motions, respectively. The bending feature associated with a double-acceptor water molecule binding to the excess electron is clearly seen up to n=35, but above n=25; this feature begins to blueshift and broadens, suggesting a more delocalized electron binding motif for the larger clusters in which the excess electron interacts with multiple water molecules. [ABSTRACT FROM AUTHOR]

The authors have investigated CO band emissions arising from the dissociative recombination of HCO+ and HOC+ ions with thermal electrons in a flowing afterglow plasma. The quantitative analysis of the band intensities showed that HCO+ recombination forms the long-lived CO(a 3Π) state with a yield of 0.23±0.12, while HOC+ recombination favors formation of CO(a′ 3Σ+) and CO(d 3Δ) with a combined yield of greater than 0.4. The observed vibrational distribution for the CO(a) state reproduces theoretical predictions quite well. The vibrational distributions for CO(a′) and CO(d) are, in part, inverted, presumably as a consequence of a change in CO equilibrium bond length during recombination. The observations are compatible with current knowledge of the potential surfaces of states of HCO and HCO+. [ABSTRACT FROM AUTHOR]

The ion-sputtering induced intermixing is studied by Monte Carlo transport of ions in matter (TRIM), molecular-dynamics (MD) simulations, and Auger electron spectroscopy depth profiling (AES-DP) analysis in Pt/Ti/Si substrate (Pt/Ti) and Ta/Ti/Pt/Si substrate (Ti/Pt) multilayers. Experimental evidence is found for the asymmetry of intermixing in Pt/Ti, and in Ti/Pt. In Ti/Pt we obtain a much weaker interdiffusion (broadening at the interface) than in Pt/Ti. The unexpected enhancement of the interdiffusion of the Pt atoms into the Ti substrate has also been demonstrated by simulations. We are able to capture the essential features of intermixing using TRIM and MD simulations for ion-beam sputtering and find reasonable values for interface broadening which can be compared with the experimental measurements. We explain the asymmetry of IM by the possible occurrence of transient enhanced diffusion in Pt/Ti which manifests in the exponential high diffusity tail of the AES concentration profile. [ABSTRACT FROM AUTHOR]

Electron-ion-coincidence spectra were recorded for K-shell excited krypton, argon, and neon clusters covering the size range from 1 atom to about 3000 atoms by utilizing hard x-ray undulator beamlines. Multiply charged ions Rz+(z>=2) and singly charged ions Rn+(n>=1) are observed as cluster fragments, and their relative abundance exhibits a characteristic dependence on the average cluster size . It is expected from these results that the charges generated on the cluster surface are strongly localized while those in the cluster core are more delocalized. The estimated charge separation distance increases with , and it is longer for lighter elements. [ABSTRACT FROM AUTHOR]

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6.0 MeV F3+ ions are implanted into x-cut LiNbO3 crystals in doses ranging from 3.0×1013 to 1.0×1015 ions/cm2 at room temperature. Planar waveguide formations are confirmed and dark modes are measured by prism coupling technique with a wavelength of 633 nm. TE modes due to both raised extraordinary index and barrier-confined waveguides are demonstrated. The Rutherford backscattering/channeling technique is used to investigate the damage produced by implantation. The experimental results are analyzed. With a fiber probe technique, the waveguide loss from TE0 mode in sample implanted with the dose of 1.0×1014 ions/cm2 is measured which is about 0.76 dB/cm after annealing. [ABSTRACT FROM AUTHOR]

A detailed theoretical study is performed on the hitherto unknown germanium cyanide radical and its ions. The 2Π state GeCN lies 5.0 kcal/mol lower than the 2Π state GeNC at the coupled-cluster theory including single and double excitations and perturbative inclusion of triple excitations [CCSD(T)]/6-311++G(3df)//quadratic configuration interaction with single and double excitations (QCISD)/6-311G(d)+zero-point vibrational energy (ZPVE) level. For interconversion between them, two electronic state pathways 2A′ and 2A″ are located, with the latter being 0.7 kcal/mol more favorable than the former. On the 2A″ path, the GeCN→GeNC and GeNC→GeCN conversion barriers are 14.5 and 9.5 kcal/mol, respectively. The detailed singlet and triplet potential-energy surfaces of both the cationic and anionic GeCN species are also investigated. On the ground-state electronic hypersurface, singlet GeNC+ is 4.6 kcal/mol more stable than singlet GeCN+, whereas triplet GeNC- is 10.0 kcal/mol less stable than triplet GeCN-. The relative energy difference between the GeCN0,± and GeNC0,± can be well correlated with the number of vacant orbitals on the Ge atom. The stability of the neutral and ionic CGeN and cyclic cGeCN is also discussed. The predicted structures, spectroscopies, ionization, and affinity energies as well as the Renner–Teller properties are expected to provide reliable estimates for future characterization of the potential GeCN and GeNC radicals as well as their ionic counterparts both in the laboratory and in the interstellar space. [ABSTRACT FROM AUTHOR]

Doppler broadening spectroscopy was performed using a variable-energy positron beam to investigate the effect of defects induced by 150-keV Ar-ion-irradiated α-Zr bulk material. S parameter in the damaged layer of the as-irradiated sample induced by ion irradiation increased with the increasing implantation dose. Isochronal annealing between 350 and 800 °C in vacuum studies was carried out to investigate the thermal stability of defects in the oxide surface and damaged layer for low-dose (1×1014 cm2) and high-dose (1×1016 cm2) irradiated samples. The results of S-W plot measured at different annealing temperatures showed that the positron-trapping center had changed. The Ar-decorated voids or vacancies, which formed in high-dose implantation samples by Ar ions combining with open-volume defects, are stable and do not recover until at high annealing temperatures. Comparing the annealing behavior of the high-dose and low-dose implantation samples show that the recovery process of open-volume defects such as vacancies and voids will be delayed by the excess Ar concentration. [ABSTRACT FROM AUTHOR]

To understand the hydration phenomena of noble transition metals, we investigated the structures, hydration energies, electronic properties, and spectra of the Cu+(H3O)1–6 and Au+(H2O)1–6 clusters using ab initio calculations. The coordination numbers of these clusters are found to be only two, which is highly contrasted to those of Ag+(H2O)n (which have the coordination numbers of 3–4) as well as the hydrated alkali metal ions (which have the coordination numbers of ∼6). For the possible identification of their interesting hydration structures, we predict their IR spectra for the OH stretch modes. [ABSTRACT FROM AUTHOR]

The blistering behavior and the exfoliation of SrTiO3 single crystals were investigated using co-implantation with boron and hydrogen. In contrast to H-only-implantation, co-implantation of B+ with 1×1015 ions/cm2 at 80 kV and H+ with 5×1016 ions/cm2 at 40 kV caused a vigorous blistering and a complete exfoliation during the annealing process. A comparison of the blistering depth and the hydrogen distribution in the co-implanted samples revealed that the exfoliation did not occur in the regions of maximum hydrogen concentration or maximum hydrogen-related radiation damage. It occurred at the crossover of the boron distribution profile and hydrogen distribution profile. With the aid of an elastic recoil detection and the Rutherford backscattering spectroscopy in the channeling mode, the preimplanted boron was found to facilitate the long-range H movement into the B-implanted region, resulting in the chemical interaction between B and H. A bond analysis obtained from the Fourier transform infrared-attenuated total reflection spectroscopy showed that B–H interactions resulted in the formation of boron hydride. It is proposed that the boron hydride formation and decomposition upon annealing provided the needed gas pressure for the complete exfoliation of B+H co-implanted SrTiO3 crystals. [ABSTRACT FROM AUTHOR]

Experimental and theoretical methodologies have been developed to determine the hyperfine structure of molecular ions from detailed studies of the Rydberg spectrum and have been tested on molecular hydrogen. The hyperfine structure in l=0–3 Rydberg states of H2 located below the X 2Σg+(v+=0,N+=1) ground state of ortho H2+ has been measured in the range of principal quantum number n=50–65 at sub-MHz resolution by millimeter wave spectroscopy following laser excitation to np and nd Rydberg states using a variety of single-photon and multiphoton excitation sequences. The np11, nd11, and the nf10–3 Rydberg states were found to be metastable and to have lifetimes of more than 5 μs beyond n=50. Members of other series, such as the nd12, nd13, and the np10 series, were found to have lifetimes of more than 1 μs. Local perturbations induced by low-n Rydberg states belonging to series converging on rovibrationally excited levels of H2+ reduce the lifetimes in narrow ranges of n values. The hyperfine structure is strongly dependent on the value of the orbital angular momentum l. In the penetrating s and p states at n≈50 the exchange interaction dominates over the hyperfine interaction and the levels can be labeled by the total electron spin angular momentum quantum number S (S=0 or 1). In the less penetrating d and f Rydberg states, the hyperfine interaction between the core nuclear and electron spins is larger than the exchange interaction and the Rydberg states are of mixed singlet and triplet character. A procedure based on the Stark effect and on the systematic analysis of selection rules and combination differences was developed to determine the orbital and the total angular momentum quantum numbers l and F and to construct an energy map of p and f Rydberg levels between n=54 and 64 with relative positions of an accuracy of better than 1 MHz. Multichannel quantum defect theory (MQDT) was extended to treat the hyperfine structure in molecular Rydberg states and was used to analyze the observed hyperfine structure of the p and f Rydberg states of H2. The frame transformation between the Born-Oppenheimer channels described by the angular momentum coupling scheme (aβJ) and the asymptotic channels described by the (e[bβS+]) coupling scheme was derived and enables an elegant treatment of all intermediate coupling cases. Purely ab initio quantum defect theory reproduced the experimentally determined positions to within 40 MHz for the p levels and 13 MHz for the f levels. By slight adjustments of the quantum defect functions and their energy dependences and by consideration of the p-f interaction, of the singlet-triplet splittings of the f levels, and of the departure of the ionic levels from pure coupling case (bβS+), the agreement between theory and experiment could be improved to 600 kHz. By comparing the results of MQDT calculations of the hyperfine structure of f Rydberg levels with those of coupled equations calculations, the frame transformation approximation of MQDT was shown to be accurate to within 300 kHz. The extrapolated ionic hyperfine structure of the X 2Σg+(v+=0,N+=1) ionic level corresponds to the ab initio prediciton of Babb and Dalgarno [Phys. Rev. A 46, R5317 (1992)] within the experimental error.© 2004 American Institute of Physics. [ABSTRACT FROM AUTHOR]

We study inelastic electron tunneling through a molecular junction using the nonequilibrium Green’s function formalism. The effect of the mutual influence between the phonon and the electron subsystems on the electron tunneling process is considered within a general self-consistent scheme. Results of this calculation are compared to those obtained from the simpler Born approximation and the simplest perturbation theory approaches, and some shortcomings of the latter are pointed out. The self-consistent calculation allows also for evaluating other related quantities such as the power loss during electron conduction. Regarding the inelastic spectrum, two types of inelastic contributions are discussed. Features associated with real and virtual energy transfer to phonons are usually observed in the second derivative of the current I with respect to the voltage [uppercase_phi_synonym] when plotted against [uppercase_phi_synonym]. Signatures of resonant tunneling driven by an intermediate molecular ion appear as peaks in the first derivative dI/d[uppercase_phi_synonym] and may show phonon sidebands. The dependence of the observed vibrationally induced lineshapes on the junction characteristics, and the linewidth associated with these features are also discussed. © 2004 American Institute of Physics. [ABSTRACT FROM AUTHOR]

The blistering behavior and the exfoliation of SrTiO3 single crystals were investigated using co-implantation with boron and hydrogen. In contrast to H-only-implantation, co-implantation of B+ with 1×1015 ions/cm2 at 80 kV and H+ with 5×1016 ions/cm2 at 40 kV caused a vigorous blistering and a complete exfoliation during the annealing process. A comparison of the blistering depth and the hydrogen distribution in the co-implanted samples revealed that the exfoliation did not occur in the regions of maximum hydrogen concentration or maximum hydrogen-related radiation damage. It occurred at the crossover of the boron distribution profile and hydrogen distribution profile. With the aid of an elastic recoil detection and the Rutherford backscattering spectroscopy in the channeling mode, the preimplanted boron was found to facilitate the long-range H movement into the B-implanted region, resulting in the chemical interaction between B and H. A bond analysis obtained from the Fourier transform infrared-attenuated total reflection spectroscopy showed that B–H interactions resulted in the formation of boron hydride. It is proposed that the boron hydride formation and decomposition upon annealing provided the needed gas pressure for the complete exfoliation of B+H co-implanted SrTiO3 crystals. [ABSTRACT FROM AUTHOR]

Experimental and theoretical methodologies have been developed to determine the hyperfine structure of molecular ions from detailed studies of the Rydberg spectrum and have been tested on molecular hydrogen. The hyperfine structure in l=0–3 Rydberg states of H2 located below the X 2Σg+(v+=0,N+=1) ground state of ortho H2+ has been measured in the range of principal quantum number n=50–65 at sub-MHz resolution by millimeter wave spectroscopy following laser excitation to np and nd Rydberg states using a variety of single-photon and multiphoton excitation sequences. The np11, nd11, and the nf10–3 Rydberg states were found to be metastable and to have lifetimes of more than 5 μs beyond n=50. Members of other series, such as the nd12, nd13, and the np10 series, were found to have lifetimes of more than 1 μs. Local perturbations induced by low-n Rydberg states belonging to series converging on rovibrationally excited levels of H2+ reduce the lifetimes in narrow ranges of n values. The hyperfine structure is strongly dependent on the value of the orbital angular momentum l. In the penetrating s and p states at n≈50 the exchange interaction dominates over the hyperfine interaction and the levels can be labeled by the total electron spin angular momentum quantum number S (S=0 or 1). In the less penetrating d and f Rydberg states, the hyperfine interaction between the core nuclear and electron spins is larger than the exchange interaction and the Rydberg states are of mixed singlet and triplet character. A procedure based on the Stark effect and on the systematic analysis of selection rules and combination differences was developed to determine the orbital and the total angular momentum quantum numbers l and F and to construct an energy map of p and f Rydberg levels between n=54 and 64 with relative positions of an accuracy of better than 1 MHz. Multichannel quantum defect theory (MQDT) was extended to treat the hyperfine structure in molecular Rydberg states and was used to analyze the observed hyperfine structure of the p and f Rydberg states of H2. The frame transformation between the Born-Oppenheimer channels described by the angular momentum coupling scheme (aβJ) and the asymptotic channels described by the (e[bβS+]) coupling scheme was derived and enables an elegant treatment of all intermediate coupling cases. Purely ab initio quantum defect theory reproduced the experimentally determined positions to within 40 MHz for the p levels and 13 MHz for the f levels. By slight adjustments of the quantum defect functions and their energy dependences and by consideration of the p-f interaction, of the singlet-triplet splittings of the f levels, and of the departure of the ionic levels from pure coupling case (bβS+), the agreement between theory and experiment could be improved to 600 kHz. By comparing the results of MQDT calculations of the hyperfine structure of f Rydberg levels with those of coupled equations calculations, the frame transformation approximation of MQDT was shown to be accurate to within 300 kHz. The extrapolated ionic hyperfine structure of the X 2Σg+(v+=0,N+=1) ionic level corresponds to the ab initio prediciton of Babb and Dalgarno [Phys. Rev. A 46, R5317 (1992)] within the experimental error.© 2004 American Institute of Physics. [ABSTRACT FROM AUTHOR]

Infrared absorption spectroscopy of few hundred H3+ ions trapped in a 22-pole ion trap is presented using chemical probing as a sensitive detection technique down to the single ion level. By exciting selected overtone transitions of the (v1=0,v2l=31)←(0,00) vibrational band using an external cavity diode laser an accurate diagnostics measurement of the effective translational and rotational temperatures of the trapped ions was performed. The absolute accuracy of the measured transition frequencies was improved by a factor of four compared to previous plasma spectroscopy measurements using velocity modulation [Ventrudo et al., J. Chem. Phys. 100, 6263 (1994)]. The observed buffer gas cooling conditions in the ion trap indicate how to cool trapped H3+ ions into the lowest ortho and para rotational states. Future experiments will utilize such an internally cold ion ensemble for state-selected dissociative recombination experiments at the heavy ion storage ring Test Storage Ring (TSR). © 2004 American Institute of Physics. [ABSTRACT FROM AUTHOR]

A detailed crystal-field splitting analysis is given for the 26 lowest-energy multiplet manifolds, 2S+1LJ, of Nd3+ (4f3) in polycrystalline ceramic garnet Y3Al5O12 (YAG). The absorption spectra obtained between 8 K and room temperature, and between 1750 and 350 nm, and the fluorescence spectrum obtained at 8 K and observed between 1450 and 875 nm are analyzed for transitions between individual energy (Stark) levels that characterize the energy-level structure of Nd3+ ions in D2 symmetry sites, replacing Y3+ ions in the garnet host lattice. A model Hamiltonian including atomic and crystal-field terms is diagonalized within the complete 4f3 SLJMJ basis set which includes 364 states. The calculated splitting of the Nd3+ energy levels by the crystal field is compared with the experimental splitting observed in both the ceramic sample and a single-crystal laser rod. Both samples have approximately the same Nd3+ concentration, about 1 at. %. By varying the atomic and crystal-field parameters, we obtain a standard deviation of 18 cm-1 between 106 calculated-to-observed Stark levels found between the ground state and the 4D1/2 at 28 369 cm-1. Within this standard deviation the energy-level structure of Nd3+ is found to be similar in both samples. Low temperature visible and near IR spectra of ceramic Nd3+:YAG show it has comparable properties to the crystalline analog. [ABSTRACT FROM AUTHOR]

A detailed crystal-field splitting analysis is given for the 26 lowest-energy multiplet manifolds, 2S+1LJ, of Nd3+ (4f3) in polycrystalline ceramic garnet Y3Al5O12 (YAG). The absorption spectra obtained between 8 K and room temperature, and between 1750 and 350 nm, and the fluorescence spectrum obtained at 8 K and observed between 1450 and 875 nm are analyzed for transitions between individual energy (Stark) levels that characterize the energy-level structure of Nd3+ ions in D2 symmetry sites, replacing Y3+ ions in the garnet host lattice. A model Hamiltonian including atomic and crystal-field terms is diagonalized within the complete 4f3 SLJMJ basis set which includes 364 states. The calculated splitting of the Nd3+ energy levels by the crystal field is compared with the experimental splitting observed in both the ceramic sample and a single-crystal laser rod. Both samples have approximately the same Nd3+ concentration, about 1 at. %. By varying the atomic and crystal-field parameters, we obtain a standard deviation of 18 cm-1 between 106 calculated-to-observed Stark levels found between the ground state and the 4D1/2 at 28 369 cm-1. Within this standard deviation the energy-level structure of Nd3+ is found to be similar in both samples. Low temperature visible and near IR spectra of ceramic Nd3+:YAG show it has comparable properties to the crystalline analog. [ABSTRACT FROM AUTHOR]

Gyrokinetic turbulence simulations covering both electron and ion spatio-temporal scales self-consistently are presented. It is found that for experimentally realistic transport levels at long wavelengths, electron temperature gradient modes may yield substantial or even dominant high-wavenumber contributions to the electron heat flux. It is investigated in which way this behavior is reflected in several experimentally accessible quantities as, for instance, density or frequency spectra. [ABSTRACT FROM AUTHOR]

Photon stimulated ion desorption and Auger decay spectra were measured for condensed thiophene around the S 1s-edge. Three kinds of ions, H+, S+, and S2+, were observed as main desorbed species. Partial ion yields (PIY) have been determined for these three fragment ions as a function of the photon energy. It was found that the indirect x-ray induced electron stimulated desorption mechanism plays an important role in H+ ion desorption. For S+ ion desorption, on the other hand, a pronounced enhancement at ∼3 eV away from the first core-to-valence resonance was observed in the PIY curve. On the basis of the results for the Auger decay spectra, the enhancement of S+ desorption at ∼3 eV away from the first resonance is interpreted in terms of the effective screening of positive holes due to the existence of Rydberg electrons. [ABSTRACT FROM AUTHOR]

In a recent experiment at Max-Born Institut, Berlin, strong modulations have been observed in energy spectra of MeV ions that were accelerated by ultrashort intense laser pulses, τL=35 fs, I=1019 W/cm2, off water droplets. This experiment is studied analytically as well as by numerical particle-in-cell simulations in one and two dimensions and it is shown how classical isothermal fluid expansion models fail in the present case. The paper investigates alternative models which claim to describe the ion spectral modulations and a mechanism that generates proton spectra similar to the experimental ones due to a simultaneous acceleration of several ion components. Finally, the issue of directional anisotropy in the spectra of accelerated ions for the case of a spherical target is discussed. [ABSTRACT FROM AUTHOR]

A Lagrangian fluid model ~cold plasma, fixed ions is developed for analyzing the coupling between electron plasma waves. This model shows that a small wave number electron plasma wave ( v2 ,k2)will strongly affect a large wave number electron plasma wave ( v1 ,k1), transferring its energy into daughter waves or sidebands at ( v11n v2 ,k11nk2) in the lab frame. The accuracy of the model is checked via particle-in-cell simulations, which confirm that the energy in the mode at ( v1 ,k1) can be completely transferred to the sidebands at ( v11n v2 ,k11nk2) by the presence of the electron plasma mode at ( v2 ,k2). Conclusive experimental evidence for the generation of daughter waves via this coupling is then presented using time- and wave number-resolved spectra of the light from a probe laser coherently Thomson scattered by the electron plasma waves generated by the interaction of a two-frequency CO2 laser with a plasma.. [ABSTRACT FROM AUTHOR]

We present a versatile new instrument capable of measuring rovibrational transition frequencies of molecular ions with sub-MHz accuracy and precision. A liquid-nitrogen cooled positive column discharge cell, which can produce large column densities of a wide variety of molecular ions, is probed with sub-Doppler spectroscopy enabled by a high-power optical parametric oscillator locked to a moderate finesse external cavity. Frequency modulation (heterodyne) spectroscopy is employed to reduce intensity fluctuations due to the cavity lock, and velocity modulation spectroscopy permits ion-neutral discrimination. The relatively narrow Lamb dips are precisely and accurately calibrated using an optical frequency comb. This method is completely general as it relies on the direct measurement of absorption or dispersion of rovibrational transitions. We expect that this new approach will open up many new possibilities: from providing new benchmarks for state-of-the-art ab initio calculations to supporting astronomical observations to helping assign congested spectra by combination differences. Herein, we describe the instrument in detail and demonstrate its performance by measuring ten R-branch transitions in the ν2 band of H3+, two transitions in the ν1 band of HCO+, and the first sub-Doppler transition of CH5+. [ABSTRACT FROM AUTHOR]

The authors have employed deep level transient spectroscopy to investigate the defects introduced in n-type Ge during 160 keV indium (In) ion implantation. Our results show that In implantation introduces three prominent electron traps with energy levels at EC-0.09 eV, EC-0.15 eV, and EC-0.30 eV, respectively. The authors have found that these defects are different from the point defects introduced by electron irradiation but that they do not involve In. Annealing at 600 °C removed all the defects introduced during In implantation but results in a single prominent defect with a level at EC-0.35 eV. [ABSTRACT FROM AUTHOR]

Recombination centers in thin asymmetrical p-n junctions were analyzed in the context of capacitance transient experiments. The combined effect of the thin low-doped region of the junction and the nonzero value of the occupation factor of the recombination center in the depletion layer caused electrons and holes to be simultaneously released from different parts of this layer during an emission transient. The need to introduce modifications in the analytical expressions that determine the parameters of these centers by capacitance transient spectroscopy is demonstrated. A correction formula to determine concentrations of electron or hole traps or recombination centers is proposed. [ABSTRACT FROM AUTHOR]

Time-resolved x-ray spectra from solid targets irradiated by the VULCAN Petawatt laser focused to 1020 W cm-2 show that material at solid density is heated to temperatures above 500 eV to a depth of about 15 μm and for a duration of more than 30 ps. Modeling with the implicit hybrid plasma code LSP shows that the heating is sensitive to the laser prepulse through resistive inhibition of the laser accelerated electrons in the blow off layer. [ABSTRACT FROM AUTHOR]