Ions In Al2O3 Research Articles

High-temperature oxidation and self-healing behavior of SiC and Ni Co-dispersed into Al2O3 matrix composite

High-temperature oxidation behavior and recovery of mechanical strength are investigated on 5 vol%Ni/Al2O3 self-healing ceramics with 1 vol% SiC co-dispersion (SiC + Ni/Al2O3). For oxidation experiment, samples were heat-treated in the temperature range of 1200–1350 °C for 24–168 h in air. For self-healing experiment, surface cracks were introduced by the Vickers indentation and then heat-treated at 1000–1300 °C for 1 and 48 h in air. The internally oxidized zone (IOZ) on SiC + Ni/Al2O3 is composed of NiAl2O4 and Al2O3 matrix. Its thickness is smaller than that of Ni/Al2O3 under the same heat-treatment conditions. The apparent activation energy on growth of IOZ for SiC + Ni/Al2O3 is approximately 680 kJ/mol, indicating that grain boundary diffusion of oxygen ion in Al2O3 is rate-controlling. Al2O3 grain boundary diffusion of oxygen ion would be suppressed by SiO2 doping via oxidation of SiC co-dispersion. Surface cracks introduced by the Vickers indentation filled with NiAl2O4. The crack disappearance rates are comparable to that of Ni/Al2O3 with Y or Si dopants. Apparent activation energy of self-healing is approximately 350 kJ/mol and its value is similar with grain boundary diffusion of Ni ions at Al2O3 matrix. Bending strengths of as-sintered and as-cracked of SiC + Ni/Al2O3 samples are 501 MPa and 114 MPa, respectively. Samples heat-treated at 1200 °C for 6 h shows bending strength up to 550 MPa, resulting in no disadvantage on the self-healing effect for SiC co-dispersion. Both of self-healing function and resistance of high-temperature internal oxidation is achieved on SiC + Ni/Al2O3.

Ce3+ Doped Al2O3-YAG Eutectic as an Efficient Light Converter for White LEDs

Ce3+ doped Al2O3-YAG eutectics were successfully grown by the horizontal directional crystallization method. The crystallization rate of eutectic growth was changed in the 1-7.5 mm/h range at a growth temperature of 1835 ℃. The microstructure of eutectic samples was investigated using scanning electron microscopy and X-ray microtomography. The intrinsic morphology of eutectic represents the stripe-like channel structure with a random distribution of the garnet Y3Al5O12 (YAG) and Al2O3 (sapphire) phases. The content of these phases in the stripes changes in the 52.9-55.3% and 46.1-47.1% ratios, respectively, depending on the growth rate of the crystallization of the eutectic samples. The luminescent properties of the eutectic demonstrated the dominant Ce3+ luminescence in the garnet phase. The luminescence of the Ce3+ ions in Al2O3 has also been observed and the effective energy transfer processes between Ce3+ ions in the Al2O3 and YAG garnet phases were revealed under high-energy excitation and excitation in the UV Ce3+ absorption bands of sapphire. The phosphor conversion properties and the color characteristics (Al2O3-YAG):Ce eutectic with different thicknesses were investigated under excitation by a blue LED. We have also tested the prototypes of white LEDs, prepared using a blue 450 nm LED chip and (Al2O3-YAG):Ce eutectic photoconverters with 0.15 to 1 mm thicknesses. The results of the tests are promising and can be used for the creation of photoconverters for high-power white LEDs.

An old system revisited: Al2O3:Ti3+ - Microscopic crystal field effects explored by the crystal field and first-principles calculations

The exchange charge model of crystal field has been used to analyze the microscopic crystal field in the Al2O3:Ti3+ system. The effects of lattice relaxation upon doping were treated in the framework of density functional based calculations of the optimized geometry of the doped host. The optimized Al2O3:Ti3+ structure was used as an input for the calculations of distance dependence of the crystal field parameters and crystal field splittings of the Ti3+ 3d states. From these calculations, the constants of the electron-vibrational interaction and the Stokes shift between the absorption and emission spectra of Ti3+ ions in Al2O3:Ti3+ were estimated to yield good agreement with the experimental results. In addition, four parameters of the superposition model of the crystal field (which in general are considered as the fitting parameters) were extracted from the results of the exchange charge model calculations. The proposed method of linking together two independent models of the crystal field is a reliable way of calculating the superposition model parameters (rather than allowing them to vary freely) and can be readily applied to other systems.

An XAFS study of the local structure of Eu<sup>3+</sup> ions in glasses prepared by a levitation technique

The local structure around Eu3+ ions in Eu-doped glasses prepared by a levitation technique was analyzed by X-ray absorption fine structure spectroscopy. The X-ray absorption near edge structure spectra demonstrated that Eu3+ ions in Al2O3–SiO2 binary glasses were partly reduced during high-temperature melting. Extended X-ray absorption fine structure spectra indicated that in La2O3–Nb2O5, La2O3–Al2O3, and La2O3–TiO2 glasses that contained a large amount of La2O3, the bond lengths between Eu and O were distributed from 2.34 to 2.39 Å. The coordinated polyhedra around the Eu ions could be fitted to a single coordination sphere. It was found that the bond lengths tend to become shorter as the optical basicity of the glass increases. In the Al2O3–SiO2 glasses without any network modifiers, the local structure around the Eu was more complex, leading to the broader first correlation peak of radial structure function.

Mechanism of the formation of novel Al2-xHfxO3 materials via a combustion synthesis method

In this paper, the synthesis mechanism of novel hafnium-doped alumina, Al2-xHfxO3 (x ​= ​0.001, 0.002 and 0.003) materials have been successfully formed via a self-propagating combustion (SPC) method. In-depth study of the materials through characterization by simultaneous thermogravimetric analysis (STA), X-ray diffraction (XRD), field emission scanning electron microscope (FESEM) and energy dispersive X-ray (EDX) were systematically done. STA technique were used to characterize the thermal profile of the precursors. From the analysis, the synthesis mechanism of the materials was proposed. XRD results reveal that hafnium doped materials correspond to the hexagonal crystal structure of Al2O3 that shows a success of the substitutional doping. The FESEM micrographs shown that the morphology of the materials was not significantly affected by the dopant concentrations. However, the presence of Hf4+ ions in Al2O3 were confirmed where the synthesized stoichiometry of all materials were perfectly identical to the obtained stoichiometry from EDX.

Ce3+/Eu2+ Doped Al2O3 Coatings Formed by Plasma Electrolytic Oxidation of Aluminum: Photoluminescence Enhancement by Ce3+→Eu2+ Energy Transfer

Plasma electrolytic oxidation (PEO) of aluminum in electrolytes containing CeO2 and Eu2O3 powders in various concentrations was used for creating Al2O3 coatings doped with Ce3+ and Eu2+ ions. Phase and chemical composition, surface morphology, photoluminescence (PL) properties and energy transfer from Ce3+ to Eu2+ were investigated. When excited by middle ultraviolet radiation, Al2O3:Ce3+/Eu2+ coatings exhibited intense and broad emission PL bands in the ultraviolet/visible spectral range, attributed to the characteristic electric dipole 4f05d1→4f1 transition of Ce3+ (centered at about 345 nm) and 4f65d1→4f7 transition of Eu2+ (centered at about 405 and 500 nm). Due to the overlap between the PL emission of Al2O3:Ce3+ and the PL excitation of Al2O3:Eu2+, energy transfer from Ce3+ sensitizer to the Eu2+ activator occurs. The energy transfer is identified as an electric dipole–dipole interaction. The critical distance between Eu2+ and Ce3+ ions in Al2O3 was estimated to be 8.6 Å by the spectral overlap method.

Indentation residual stresses in soda-lime and borosilicate glasses

Residual stress measurements by fluorescence microscopy is a well-established technique which uses the R1 and/or R2 fluorescence peaks of Cr+3 ions in Al2O3. These peaks are sensitive to the distortion of the lattice and their position changes if the crystal is stressed. Borosilicate (BS) and soda-lime (SL) composites with 10 vol% Al2O3 were produced mixing the glass and alumina powders, uniaxially compressed and sintered at high temperature. Surface morphology and microstructure were characterized by optical and scanning electron microscopies. The porosity obtained was <2%. 10 N Vickers indentations were performed and the stresses around the indentations were measured by fluorescence microscopy. Measurements of residual stresses, due to thermal expansion mismatch between the glass matrix and the Al2O3, were 163 MPa and −35 MPa for BS and SL composites samples, respectively, in agreement with Hseuh & Becher's model. The probe response function was fitted to the fluorescence data taking into account the iteraction of the laser beam within the sample and effects of light absorption, refraction and scattering by alumina particles and pores, and stresses gradients. The experimental fluorescence shift as a function of the distance from the indentations was compared with Yoffe's model and the PRF function. It was found that the experimental blister field strength is a factor of 10 smaller than that predicted by Yoffe's model, taking into account the densification of the glass underneath the indenter. Indentation residual stresses were also measured for SL glass using the modified Zeng and Rowcliffe's model. Stress profiles were measured around 50 N and 100 N Vickers indentations performed between −196 °C to 400 °C. The blister field strength increased with temperature and it could be explained by the variation of the E/H ratio with temperature. This work contributes for the understanding of the mechanisms responsible for the indentation residual stresses in glasses.

Photoluminescence of Ce3+ and Ce3+/Tb3+ ions in Al2O3 host formed by plasma electrolytic oxidation

In this paper, Ce3+ doped Al2O3 coatings were prepared by plasma electrolytic oxidation (PEO) processing of aluminum in electrolyte which contained CeO2 particles. The morphology, chemical composition, crystal structure, and photoluminescent (PL) properties of obtained coatings were investigated. The excitation PL spectra of Al2O3:Ce3+coatings show broad band in the range from 250 nm to 340 nm, which can be attributed to the transitions from 4f ground state of Ce3+ ions to the field splitting levels of 5d state. The emission PL spectra, obtained under 285 nm excitation, feature broad 5d→4f emission band in the ultraviolet/visible spectral range with the maximum peak located at around 345 nm. PL intensity depends of the content of Ce3+ ions incorporated into PEO coatings, i.e. PEO time and concentration of CeO2 particles in electrolyte. In addition, Ce3+ sensitized PL of Tb3+ions in Al2O3:Ce3+/Tb3+ coatings formed by PEO was examined. The emission PL spectrum of Al2O3:Ce3+/Tb3+ coating exhibits two distinct regions: the first region is related to Ce3+ PL band and the second region features a series of characteristic peaks of Tb3+ ions corresponding to 5D3→7FJ (J = 4, 5, and 6) and 5D4→7FJ (J = 3, 4, 5, and 6) transitions. A strong green 5D4→7F5 emission of Tb3+ ions upon excitation of Ce3+ is initiated by efficient energy transfer from Ce3+ to Tb3+ ions.

Photoluminescence properties of Eu3+-doped stalk-like Al2O3 via a hydrothermal route followed by heat treatment

ABSTRACTUniform Al2O3:Eu3+ samples were successfully fabricated via a hydrothermal method and subsequent thermal decomposition of Eu3+-doped precursors. The sample characterisations were carried out by means of X-ray diffraction (XRD), scanning electron microscope (SEM) and photoluminescence spectra. XRD results revealed Eu3+-doped samples were a pure γ-Al2O3 phase after being calcined at 1173 K. SEM results showed that these Eu3+-doped Al2O3 samples were stalk-like, with an average length of 1.5 μm. Upon excitation at 394 nm, the orange–red emission bands, having wavelengths longer than 580 nm, were to be from 5D0→7FJ (J = 1, 2) transitions. The asymmetry ratio of (5D0→7F2)/(5D0→7F1) intensity is about 0.54, 2.76, 3.29, 2.86, 3.36, 3.13 for Eu3+ concentrations of 0.1, 0.4, 0.7, 1.0, 1.5 and 2.0 mol-%, respectively. The optimal doping concentration of Eu3+ ions in Al2O3 is 1.5 mol-%. According to Dexter's theory, the critical distance between Eu3+ ions for energy transfer was determined to be 14 Å.

In-situ kinetics of modifications induced by swift heavy ions in Al2O3: Colour centre formation, structural modification and amorphization

This paper details in-situ studies of modifications induced by swift heavy ion irradiation in α-Al2O3. This complex behaviour is intermediary between the behaviour of amorphizable and non-amorphizable materials, respectively. A unique combination of irradiation experiments was performed at the IRRSUD beam line of the GANIL facility, with three different characterisation techniques: in-situ UV–Vis absorption, in-situ grazing incidence X-Ray diffraction and ex-situ transmission electron microscopy. This allows a complete study of point defects, and by depth profile of structural and microstructural modifications created on the trajectory of the incident ion. The α-Al2O3 crystals have been irradiated by 92 MeV Xenon and 74 MeV Krypton ions, the irradiation conditions have been chosen rather similar with an energy range where the ratio between electronic and nuclear stopping power changes dramatically as function of depth penetration. The main contribution of electronic excitation, above the threshold for track formation, is present beneath the surface to finally get almost only elastic collisions at the end of the projected range. Amorphization kinetics by the overlapping of multiple ion tracks is observed. In the crystalline matrix, long range strains, unit-cell swelling, local microstrain, domain size decrease, disordering of oxygen sublattice as well as colour centre formation are found. This study highlights the relationship between ion energy losses into a material and its response. While amorphization requires electronic stopping values above a certain threshold, point defects are predominantly induced by elastic collisions, while some structural modifications of the crystalline matrix, such as unit-cell swelling, are due to contribution of both electronic and nuclear processes.

Investigations of defect structures and g factors for octahedral (CrO6)7− and (VO6)8− clusters in rutile-type crystals

The electron paramagnetic resonance (EPR) [Formula: see text] factor formulas for Cr[Formula: see text] and V[Formula: see text] ions in Al2O3, TiO2 and VO2 crystals are deduced from Jahn–Teller effect and contributions of the charge transfer (CT) levels. The tetragonal distortions. [Formula: see text] and −0.0124 nm, and [Formula: see text], [Formula: see text] and 0[Formula: see text], for Al2O3:Cr[Formula: see text], TiO2:V[Formula: see text] and VO2, respectively. The calculations of the [Formula: see text] factors agree well with the experimental values. The contributions of the CT levels to [Formula: see text] factors increase with the increasing valence state. It must be taken into account in the precise calculations of [Formula: see text] factors for the high valence state [Formula: see text] ions in crystals.

Photoluminescence properties of Tb3+-doped stalk-like Al2O3

AbstractUniform Al2O3 : Tb3+ samples were successfully fabricated via a hydrothermal method and subsequent thermal decomposition of Tb3+ doped precursors. Scanning electron microscopy results showed Tb3+-doped Al2O3 was stalk-like with an average length about 1.5 μm. Photoluminescence spectra indicated that the 5D4 → 7F5 (545 nm) electric dipole transition was most intense upon excitation at 227 nm. It is shown that 1.5 mol.% doping concentration of Tb3+ ions in Al2O3 : Tb3+ is optimum. According to Dexter's theory, the critical distance between Tb3+ ions in Al2O3 for energy transfer was determined to be 14 Å.

Europium-doped fiber-like Al2O3 and its photoluminescence properties

Uniform Al2O3:Eu3+ microfibres were synthesized via a hydrothermal route and heat treatment (1173 K/2 h) of a precursor of Eu3+-doped ammonium aluminium hydroxide carbonate (NH4Al(OH)2CO3). The length and diameter of these Eu3+-doped Al2O3 microfibres are about 4–7 μm and 400 nm, respectively. Upon excitation at 394 nm, the orange-red emission bands were from 5D0 → 7FJ (J = 1, 2) transitions. The asymmetry ratio of (5D0 → 7F2)/(5D0 → 7F1) intensity is about 0.99, 1.43, 2.24, 2.40, 1.63 for the Eu3+ concentration 0.05, 0.30, 0.70, 0.90 and 1.20 mol-%, respectively. These values suggest that the asymmetry ratio of Eu3+ ions is related to the doping concentration. The maximum doping concentration of Eu3+ ions in Al2O3 is 0.9 mol-%. According to Dexter’s theory, the critical distance between Eu3+ ions for energy transfer was determined to be 17 Å.

Latent tracks and associated strain in Al2O3 irradiated with swift heavy ions

The morphology of latent ion tracks induced by high energy heavy ions in Al2O3 was investigated using a combination of high resolution transmission electron microscopy (HRTEM), exit wave reconstruction, geometric phase analysis and numerical simulations. Single crystal α-Al2O3 crystals were irradiated with 167MeV Xe ions along the c-axis to fluences between 1×1010 and 1×1013cm−2. Planar TEM lamella were prepared by focused ion beam (FIB) and geometrical phase analysis was performed on the phase image of the reconstructed complex electron wave at the specimen exit surface in order to estimate the latent strain around individual track cores. In addition to the experimental data, the material excitation in a SHI track was numerically simulated by combining Monte-Carlo code, describing the excitation of the electronic subsystem, with classical molecular dynamics of the lattice atoms. Experimental and simulation data both showed that the relaxation of the excess lattice energy results in the formation of a cylinder-like disordered region of about 4nm in diameter consisting of an underdense core surrounded by an overdense shell. Modeling of the passage of a second ion in the vicinity of this disordered region revealed that this damaged area can be restored to a near damage free state. The estimation of a maximal effective distance of recrystallization between the ion trajectories yields values of about 6–6.5nm which are of the same order of magnitude as those estimated from the saturation density of latent ion tracks detected by TEM.

Molecular Dynamics Simulation of Dipole Layer Formation at High-k/SiO2 Interfaces

Implementation of high-k/metal gate stack poses a challenge in controlling the threshold voltage (VTH) of MOSFET devices. Recent studies have shown that an electric dipole layer formed at high-k/SiO2 interface is responsible for anomalous VTH shifts. The origin of the dipole layer has been explained by several mechanisms, such as the areal density difference of O atoms [1], electronegativity difference [2], and contact induced gap state [3]. Among these models, the first model proposed by Kita and Toriumi [1] is noteworthy because of its simplicity and potential to be applicable to wide variety of high-k materials. The model states that the interface dipole is formed by the movement of negatively charged O ions from higher oxygen-density side to a lower one.Recently, we performed molecular dynamics (MD) simulations of high-k/SiO2 interfaces and succeeded in reproducing the O atom migration across the Al2O3/SiO2 interface [4]. The O ion moves one-sidedly from Al2O3 side to SiO2 one, but opposite movement never occurs. The simulation result implies that the O ion migration is induced by some drift forces, but not by a simple diffusion due to the O density gradient across the high-k/SiO2. In this paper, we discuss the driving force of the O ion migration across the high-k/SiO2 in terms of the multipole moment around oxide cation.The MD simulation was performed by a commercial simulation package SCIGRESS ME from Fujitsu Ltd. Al2O3/SiO2 interface model was constructed by sandwiching amorphous Al2O3 blocks in between amorphous SiO2 blocks as shown in Fig.1. The hetero-oxide structure was annealed by the isothermal-isobaric MD calculation for 100 ps, thermostated at 1000 K by a velocity scaling with keeping the pressure at atmospheric pressure. The Born-Mayer-Huggins potential is employed in the MD simulation.Figure 2(a) shows a charge density profile across the SiO2/Al2O3 interface. Electric dipole layer appears at the interface, and it is directed from the SiO2 side to Al2O3 side. Figure 2(b) shows the electric potential profile around the interface, which is obtained by solving one-dimensional Poisson’s equation. The built-in potential at SiO2/Al2O3 interface is about 0.5 V, which matches the experimental value of the flat-band voltage shift [1]. Thus the direction and magnitude of the dipole moment in our model agrees with the experimental result. Figure 3 shows the magnified image of the SiO2/Al2O3 interface, in which the O ions originated from Al2O3 are colored by green. It can be clearly seen that the O ion moves one-sidedly from Al2O3 side to SiO2 one.The simulation result indicates that the O ion is driven by some drift forces, but not by a simple diffusion due to the density difference at the interface. It is inferred that the O ions in Al2O3 are attracted to the strong positive charges of Si ions. The positive charges of Si ions must be canceled by the negative charges of O ions in SiO2, but at very close distance, there is an appreciable octupole moment around the Si ion which is located at the center of SiO4 tetrahedron (see Fig.4). On the other hand, there is an hexadecapole moment around the Al ion which located at the center of AlO6octahedron. The electrostatic field induced by the octupole moment around the Si ion is stronger than that of the hexadecapole moment around the Al ion, and thus O ions in the vicinity of the interface can be attracted to Si ions in specific directions. Opposite dipole formation at SiO2/Y2O3interface can also be explained by the difference in the multipole moments around Si and Y ions [4].The multipole moment around an oxide cation is relevant to its electronegativity of the O density of the oxide. Therefore, our “multipole moment induced O migration model” can be regarded as the unified model of the O density [1] model and the electronegativity model [2]. Acknowledgement This work is supported by JST-CREST, and a Grant-in-Aid for Scientific Research (B) from the MEXT Japan.

The Research on Preparation Process Optimization of Ion Barrier Film on the Input Side of MCP

Micro-channel Plate (MCP) with Ion Barrier Film(IBF) is one of the main technical indicators that restrict the performance of the third generations of Low Light Level Image Intensifier(LLLII). IBF with inferior quality can be a direct impact on the performance of the third generations of LLLII or even makes it not work, and it’s very unfavorable in the tube mass production and promotion. In response to this urgent requirement, in order to improve the quality and preparation of the finished product of the Al2O3 on the input side of MCP prepared by magnetron sputtering, the paper carries out the process optimization of magnetron sputtering used for image intensifier. By simulation of Ar ion bombarding Al2O3 target, while under the guidance of the working principles of the magnetron sputtering and thin film growth theory, we change the working pressure、 sputtering power、 argon flow and other process parameters by using magnetron sputtering machine developed in China, to change the coating deposition rate of Al2O3, and to increase the lateral migration of the film-forming process of Al2O3. Finally we prepare a uniform、 continuous and compact Al2O3 Ion Barrier Film. At last the optimal technique is obtained: Sputtering pressure is 2.6×10-1Pa, Ar2 flux is 90sccm, sputtering power is 170W, and the thickness of film is 80Å. We test the performance of MCP with optimized films by using the MCP performance testing devices, contrasting with pre-fabricated thin-film quality, and the results show that the average gain decline is dropped, the dead volt is lower, and the quality of the films prepared by this process is significantly better, yield and view pass rate is as high as 90%, meeting the dual demands of high electronic transmittance and high ion blocking rate of IBF.

Comparative study of the luminescence of Al2O3:Ti and Al2O3 crystals under VUV synchrotron radiation excitation

The comparative study of the luminescent properties of Al2O3:Ti crystal in comparison with those for undoped Al2O3 crystal counterpart is performed under synchrotron radiation excitation with an energy of 3.7–25eV. Apart from the main emission band peaked at 725nm related to the 2E→2T2 radiative transitions of Ti3+ ions, the luminescence of excitons localized around Ti ions in the band peaked at 290nm and the luminescence of F+–Ti and F–Ti centers in the bands peaked at 325 and 434nm are also found in the emission spectra of Al2O3:Ti crystal. We show also that the luminescence of Ti3+ ions in Al2O3:Ti crystal can be effectively excited by the luminescence of excitons localized around Ti dopant as well as by the luminescence of F–Ti centers.

The Formation of Super-Thin Dielectric Film on Porous Substrate and its Stopping – Transmittance Characteristics for Particles

The formation of super-thin continuous dielectric film (e.g. the ion barrier film-IBF) on microchannel plate (a kind of porous substrate) is most important for prolonging the operating life of the third generation micro-light image tube. In this paper, firstly, the formation of Al2O3 ion barrier film on microchannel plate (MCP) using a new contamination-free technology was introduced. According to the analysis and the comparison with the traditional direct formation technology, it was found that the productivity of the new technology is better (90%) and the carbon contamination can be minimized. Next, the stopping and transmittance characteristic of the film for electrons were studied and the measurement principle was shown. In this measurement, the concepts of “dead-voltage” and “electron transmittance” were proposed to evaluate the stopping and transmittance of the film for electrons. The dead-voltage was 220V for the MCP covered the ion barrier film with a thickness of 5nm and the electron transmittance was over 90%.

Tuning the Er3+ sensitization by Si nanoparticles in nanostructured as-grown Al2O3 films

Nanostructured films consisting of single Si nanoparticles (NPs) and Er3+ ions layers separated by nanometer-scale Al2O3 layers of controlled thickness have been prepared in order to tune the energy transfer between Si NPs and Er3+ ions. The amorphous Si NPs with an effective diameter of ∼4.5 nm are formed during growth and are able to sensitize the Er3+ ions efficiently with no postannealing treatments. The characteristic distance for energy transfer from Si NPs to Er3+ ions in Al2O3 is found to be in the 1 nm range. It is shown that in the nanostructured films, it is possible to achieve an optimized configuration in which almost all the Er3+ ions have the potential to be excited by the Si NPs. This result stresses the importance of controlling the dopant distribution at the nanoscale to achieve improved device performance.

Stopping Power Calculations of Compounds by Using Thomas-Fermi-Dirac-Weizsäcker Density Functional

Electronic stopping power of compounds was calculated by using the Thomas–Fermi–Dirac–Weizsacker density functional. Bragg’s rule was employed to determine stopping power of compounds from the elemental stopping power results. Calculations were done for Be, B, O, and Si ions in Al2O3, SiO2, and CO2 targets by using the Thomas–Fermi–Dirac–Weizsacker density functional. The obtained results were compared with other Thomas– Fermi based theoretical calculations and show that using Thomas–Fermi– Dirac–Weizsacker density functional in stopping power calculations yields reasonably accurate results in especially light systems (with respect to the number of electrons in the system).