Superhyperfine Interaction Research Articles

Luminescence‐detected EPR of oxygen‐fluorine vacancy complexes in CaF2

AbstractIn several CaF2 single crystals grown by the Bridgman method and doped with CaO or in addition with SrF2 or NaF a luminescence band between 470 nm and 600 nm could be excited at 212 nm, its peak wavelength depending on the doping. With photo‐luminescence (PL) detected EPR five spin triplet centres were identified. Their axial fine structure constants D varied from 87 mT to 690 mT whereby the most intense spectra had the smallest D value. Theoretical calculations of the fine structure tensors and superhyperfine interactions show that the most intense and probable triplet centre consists of a pair of an OF– on a F– site next to a nearest neighbour F– vacancy which, compared to the well‐known F centre, is occupied by an excited electron in a shallow orbital and coupled to the 2p hole at the oxygen to form a S = 1 excited state. This centre can be excited optically at low temperature to a metastable new configuration where the F centre jumps into a 〈111〉 position opposite the OF–. The other triplet centres have probably also an O––F centre nearest neighbour configuration but have in addition a cation impurity or vacancy nearby. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Pleomorphic Copper Coordination by Alzheimer’s Disease Amyloid-β Peptide

Numerous conflicting models have been proposed regarding the nature of the Cu(2+) coordination environment of the amyloid beta (Abeta) peptide, the causative agent of Alzheimer's disease. This study used multifrequency CW-EPR spectroscopy to directly resolve the superhyperfine interactions between Cu(2+) and the ligand nuclei of Abeta, thereby avoiding ambiguities associated with introducing point mutations. Using a library of Abeta16 analogues with site-specific (15)N-labeling at Asp1, His6, His13, and His14, numerical simulations of the superhyperfine resonances delineated two independent 3N1O Cu(2+) coordination modes, {N(a)(D1), O, N(epsilon)(H6), N(epsilon)(H13)} (component Ia) and {N(a)(D1), O, N(epsilon)(H6), N(epsilon)(H14)} (component Ib), between pH 6-7. A third coordination mode (component II) was identified at pH 8.0, and simulation of the superhyperfine resonances indicated a 3N1O coordination sphere involving nitrogen ligation by His6, His13, and His14. No differences were observed upon (17)O-labeling of the phenolic oxygen of Tyr10, confirming it is not a key oxygen ligand in the physiological pH range. Hyperfine sublevel correlation (HYSCORE) spectroscopy, in conjunction with site-specific (15)N-labeling, provided additional support for the common role of His6 in components Ia and Ib, and for the assignment of a {O, N(epsilon)(H6), N(epsilon)(H13), N(epsilon)(H14)} coordination sphere to component II. HYSCORE studies of a peptide analogue with selective (13)C-labeling of Asp1 revealed (13)C cross-peaks characteristic of equatorial coordination by the carboxylate oxygen of Asp1 in component Ia/b coordination. The direct resolution of Cu(2+) ligand interactions, together with the key finding that component I is composed of two distinct coordination modes, provides valuable insight into a range of conflicting ligand assignments and highlights the complexity of Cu(2+)/Abeta interactions.

Electron spin resonance study of self-trapped holes in CdWO4 scintillator crystals

The self-trapping of holes at oxygen anions was studied by electron spin resonance in UV irradiated CdWO4 crystals. Analysis of superhyperfine interaction of the holes with W183 and C111,113d isotopes shows that the self-trapped hole is either delocalized in the space between two energetically equivalent nearest neighbor oxygen ions or tunnels between them. When the temperature increases above 40–50 K the self-trapped holes are thermally liberated and can be retrapped by oxygen ions perturbed by impurity ions. In case of the Nb5+ or Li+ stabilizing impurities the O− centers are thermally stable up to 160–170 K. The study of kinetic characteristics of the self-trapped holes suggests that holes leave oxygen ions by thermally assisted tunneling mechanism via two slightly different channels. Corresponding ionization probabilities are defined by the Arrhenius law with an average thermal ionization energy E=90(5) meV. Calculated pre-exponential factors, about 105 s−1, are small, which is consistent with the tunneling mechanism. Thermal stability and kinetic characteristics of the trapped holes are discussed in light of the scintillation and thermoluminescence characteristics of CdWO4.

Bioinorganic chemistry: a short course

Chapter 1: Inorganic Chemistry Essentials. Introduction . Essential Chemical Elements. Metals in Biological Systems: A Survey. Inorganic Chemistry Basics. Biological Metal Ion Complexation. Thermodynamics. Kinetics. Electronic and Geometric Structures of Metals in Biological Systems. Bioorganometallic Chemistry. Electron Transfer. Introduction to Biological Metal Homeostasis, Transport, and Storage. Chapter 2: Biochemistry Fundamentals. Introduction. Proteins. Amino Acid Building Blocks. Protein Structure. Protein Sequencing and Proteomics. Protein Function, Enzymes and Enzyme Kinetics. Nucleic Acids. DNA and RNA Building Blocks. DNA and RNA Molecular Structures. Transmission of Genetic Information. Genetic Mutations and Site-Directed Mutagenesis. Genes and Cloning. Genomics and the Human Genome. The ATP-binding cassette (ABC) Transporter Superfamily. Chapter 3: Instrumental Methods. Introduction. Analytical Instrument-Based Methods. Spectroscopy. X-ray Absorption Spectroscopy (XAS) and Extended X-ray Absorption Fine Structure (EXAFS). Theoretical Aspects and Hardware. Descriptive Examples. X-ray Crystallography. Introduction. Crystallization and Crystal Habits. Theory and Hardware. Descriptive Examples. Electron Paramagnetic Resonance. Theory and Determination of g-values. Hyperfine and Superhyperfine Interactions. Descriptive Examples. Nuclear Magnetic Resonance. Theoretical Aspects. Nuclear Screening and the Chemical Shift. Spin-Spin coupling. Techniques of Spectral Integration and Spin-Spin Decoupling. Nuclear Magnetic Relaxation. The nuclear Overhauser Effect (NOE). Obtaining the NMR spectrum. Two-dimensional NMR Spectroscopy. Correlation Spectroscopy (COSY). Nuclear Overhauser Effect Spectroscopy (NOESY). Descriptive Examples. Mossbauer Spectroscopy. Theoretical Aspects. Quadrupole Splitting and the Isomer Shift. Magnetic Hyperfine Interactions. Descriptive Examples. Atomic Force Microscopy. Fast Methods. Stopped-Flow Kinetic Methods. Flash Photolysis. Time-Resolved Crystallography. Chapter 4: Introduction to Computer-Based Methods. Computer Hardware . Molecular Modeling and Molecular Mechanics. Introduction to MM. Molecular Modeling, Molecular Mechanics and Molecular Dynamics. Biomolecule Modeling. Molecular Modeling Descriptive Examples. Quantum Mechanics-Based Computational Methods. Introduction. Ab-initio Methods. Density Functional Theory. Semi-empirical Methods. Computer Software for Chemistry. Mathematical Software. World Wide Web Online Resources. Nomenclature and Visualization Resources. Online Societies, Literature, Materials, Equipment Webservers. Chapter 5: Group I and II metals in biological systems. Transport and storage of metal ions. Homeostasis involving Na+, K+, Ca2+, Mg2+, Zn2+ (as well as P, Cl, and H). Movement of molecules and ions across membranes. Proton pumps. Ion pumps. Active versus passive transport . Na+/ K+ ATPases. Magnesium dependent biomolecules. Kinases. ATP-pumps. Catalytic RNA and Magnesium. Magnesium in chlorophyll. Calcium dependent biomolecules. Calmodulins and triggering. Biochemistry of nitrogen oxides, nitroxyl, and peroxynitrite ion. Chapter 6: Iron Containing Proteins and Enzymes. Iron-containing proteins with porphyrin ligand systems. Hemoglobin and Myoglobin (first edition material somewhat condensed). Cytochrome P-450: a monooxygenase. Iron-containing cytochromes in photosynthesis. Green plant cytochromes. Cytochrome bc559. Cytochrome bf. Bacterial cytochromes. Cytochrome c2. Cytochrome bc1. Iron-containing cytochromes in the respiratory pathway. Cytochrome c. Cytochrome c oxidase. Non-Heme Iron-containing proteins. MMO-Methane Monooxygenase. Catechol dioxygenases. Iron-oxo clusters. Transferrin for metal transport . Ferritin for metal storage. Hemerythrin. Purple acid phosphatase. Iron-sulfur cluster proteins. Rubredoxin. Ferrodoxins. Aconitase. Chapter 7: Enzymes containing zinc, nickel, and enzymes with multiple metal cofactors. Zinc homeostasis, transport, and storage. Zinc Enzymes. Alkaline phosphatase. Alcohol dehydrogenase. Aspartate transcarbamoylase. Carbonic anhydrase. Carboxypeptidase A and B. Zinc Fingers. Nickel Enzymes. Urease. F430. Enzymes with multiple metal cofactors. Hydrogenases. Carbon monoxide dehydrogenases. Chapter 8 Disease, Disease Diagnosis and Treatment Utilizing Inorganic Species. Metal Transport and Metallochaperones. Disease States. Metal deficiency. Metal toxicity. Copper toxicity. FALS. Wilson and Menkes diseases. Disease Diagnosis. Technetium Imaging Agents. Gadolinium MRI Imaging Agents. Quantum Dots for In vivo Imaging. Metals in Medicine. Manganese superoxide mimetics. Vanadium-based Diabetes Drugs. Platinum-containing Anticancer Agents. Nanomedicine.

Structural basis for VO2+ inhibition of nitrogenase activity (A): 31P and 23Na interactions with the metal at the nucleotide binding site of the nitrogenase Fe protein identified by ENDOR spectroscopy

We previously reported the vanadyl hyperfine couplings of VO(2+)-ATP and VO(2+)-ADP complexes in the presence of the nitrogenase Fe protein from Klebsiella pneumoniae (Petersen et al. in Biochemistry 41:13253-13263, 2002). It was demonstrated that different VO(2+)-nucleotide coordination environments coexist and are distinguishable by electron paramagnetic resonance (EPR) spectroscopy. Here orientation-selective continuous-wave electron-nuclear double resonance (ENDOR) spectra have been investigated especially in the low-radio-frequency range in order to identify superhyperfine interactions with nuclei other than protons. Some of these resonances have been attributed to the presence of a strong interaction with a 31P nucleus although no resolvable superhyperfine structure due to 31P or other nuclei was detected in the EPR spectra. The superhyperfine coupling component is determined to be about 25 MHz. Such a 31P coupling is consistent with an interaction of the metal with phosphorus from a directly, equatorially coordinated nucleotide phosphate group(s). Additionally, novel more prominent 31P ENDOR signals are detected in the low-frequency region. Some of these correspond to a relatively weak 31P coupling. This coupling is present with ATP for all pH forms but is absent with ADP. The ENDOR resonances of these weakly coupled 31P are likely to originate from an interaction of the metal with a nucleotide phosphate group of the nucleoside triphosphate and are attributed to a phosphorus with axial characteristics. Another set of resonances, split about the nuclear Zeeman frequency of 23Na, was detected, suggesting that a monovalent Na+ ion is closely associated with the divalent metal-nucleotide binding site. Na+ replacement by K+ unambiguously confirmed that ENDORs at radio frequencies between 3.0 and 4.5 MHz arise from an interaction with Na+ ions. In contrast to the low-frequency 31P signal, these resonances are present in spectra with both ADP and ATP, and for both low- and neutral-pH forms, although slight differences are detected, showing that these are sensitive to the nucleotide and pH.

Superhyperfine Interaction in [MnF6]3−

Endlich aufgelöst: Ein konventionelles Spektrometer erbrachte das erste EPR-Spektrum eines Mangan(III)-Komplexes – [MnF6]3− – mit hochaufgelöster Superhyperfeinstruktur. Es wird gezeigt, wie die Art der Jahn-Teller-Verzerrung und die elektronische Struktur (siehe Bild) aus einem einzelnen EPR-Spektrum ermittelt werden können und wie sich die elektronische Struktur des Zentralions in der Superhyperfeinwechselwirkung mit den umgebenden Liganden widerspiegelt.

Superhyperfine Interaction in [MnF6]3−

Resolved at last: A conventional spectrometer afforded the first EPR spectrum of a manganese(III) complex, namely [MnF6]3−, featuring clearly resoved superhyperfine interactions. It is shown how the nature of the Jahn–Teller distortion and the concomitant electronic structure (see picture) can be deduced from a single EPR spectrum and how the electronic structure of the central ion is reflected in the superhyperfine interaction with the surrounding ligands.

The cis/trans isomerization of Cu(II)–bis‐(glycinato) complex in solution: a computer aided multifrequency EPR and DFT/PCM calculation study

In this paper the Cu(II)-bis-(glycinato) complex has been analysed in solution by applying a combined approach of multifrequency EPR and DFT/PCM calculations. The accuracy in the determination of magnetic parameters has been reached by the use of a unique simulation program (COSMOS) for the whole range of temperatures analysed and by the error analysis. A change in magnetic parameters was envisaged in the 243-253 K range of temperature, and was interpreted in terms of stabilization, near the freezing point of the solution, of one of the isomers of the complex. A DFT/PCM computational model was crucial in assigning, on the basis of the experimental superhyperfine interaction value, the isomer to the trans form.

EPR line width and spin-relaxation rates of shallow and deep donors in isotopically controlled silicon

The results of a numerical calculation of the contribution of ligand superhyperfine interactions to the line width for the phosphorus donor electron in silicon are reported and show linear behavior at lower concentrations compared to deep centers. The linear dependence for the phosphorus center in silicon predicts an electron spin-relaxation time for isotopically purified Si 28 : P longer than expected on the basis of the common square-root law. The confrontation of line width in deep-level centers with shallow states confirms that the behavior depends on the distribution of spin density around the paramagnetic center.

Investigations of optical coherence properties in an erbium-doped silicate fiber for quantum state storage

We studied optical coherence properties of the 1.53μm telecommunication transition in an Er3+-doped silicate optical fiber through spectral holeburning and photon echoes. We find decoherence times of up to 3.8μs at a magnetic field of 2.2T and a temperature of 150mK. A strong magnetic-field dependent optical dephasing was observed and is believed to arise from an interaction between the electronic Er3+ spin and the magnetic moment of tunneling systems in the glass. Furthermore, we observed fine-structure in the Erbium holeburning spectrum originating from superhyperfine interaction with 27Al host nuclei. Our results show that Er3+-doped silicate fibers are promising material candidates for quantum state storage.

EPR properties of Au atoms adsorbed on various sites of the MgO(1 0 0) surface from relativistic DFT calculations

Using all electron fully relativistic DFT calculations we have computed the EPR properties of Au atoms bound to various sites of the MgO surface. Changes in g-tensor and hyperfine coupling constants provide a way to identify the gold adsorption site and to map the surface morphology by comparison of measured and calculated EPR spectra. We found a strong reduction of the isotropic hyperfine coupling constant, a iso(Au), for adsorbed gold compared to the free atom; this reduction, which is about 45% for terrace sites, is more pronounced when Au interacts with low-coordinated sites like steps, edges and corners where it is about 60%. The reduction of a iso(Au) is accompanied by a corresponding increase of the superhyperfine interaction with the surface oxygen sites, as measured by a iso( 17O). Large anisotropies in the g-tensor are computed for all sites.

Electron-trapping centers and interstitials in chlorinatedSrCl2:Fesingle crystals

Electron-trapped ${\mathrm{Fe}}^{+}$-type centers, produced by x-ray irradiation at $80\phantom{\rule{0.3em}{0ex}}\mathrm{K}$ and further annealing at higher temperatures in iron-doped ${\mathrm{SrCl}}_{2}$ single crystals grown in chlorine gas, have been investigated by electron paramagnetic resonance. The ${\mathrm{Fe}}^{+}(\mathrm{III})$ and ${\mathrm{Fe}}^{+}(\mathrm{IIIa})$ centers, produced by annealing at temperatures higher than $200\phantom{\rule{0.3em}{0ex}}\mathrm{K}$, exhibit monoclinic local symmetry with the two $\stackrel{⃡}{g}$- tensor principal axes situated in the (110) plane slightly tilted away from the [001] and [1--10] directions, respectively. The ${\mathrm{Fe}}^{+}(\mathrm{IV})$ center, observed after several cycles of irradiation and annealing to $700\phantom{\rule{0.3em}{0ex}}\mathrm{K}$, exhibits tetragonal local symmetry around $⟨100⟩$ and a well-resolved four-component structure, attributed to the superhyperfine interaction with a neighboring monovalent impurity ion. The presence and properties of the low symmetry radiation-induced ${\mathrm{Fe}}^{+}$ paramagnetic centers are attributed to trapping and the thermally activated movement of chlorine interstitials. Both precursor ${\mathrm{Fe}}^{2+}$ and resulting ${\mathrm{Fe}}^{+}$ centers are perturbed by these interstitials, which are introduced in ${\mathrm{SrCl}}_{2}:\mathrm{Fe}$ crystals during growth under a chlorine atmosphere.

EPR of Pb3+ ion in LiBaF3 crystals

Complex EPR spectra of paramagnetic centers Pb3+ formed in LiBaF3:Pb2+ crystals under X-ray irradiation are studied in the temperature range of 10–150 K. It is shown that lead ions substitute Ba2+ ions in the LiBaF3 crystal and are in the cubic-octahedral 12-fold environment of the fluorine ions. The hyperfine structure constants describing the observed spectrum are determined and parameters of superhyperfine interaction with the nearest fluorine ions are estimated.

The contribution of 29Si ligand superhyperfine interactions to the line width of paramagnetic centers in silicon

The results of a numerical approach for the modeling of the contribution of ligand superhyperfine interactions to the line width of the paramagnetic negative vacancy and of positively charged iron centers in silicon are reported. The dependence which is obtained for the contribution to the line width on the concentration of magnetic nuclei has a linear character for low concentrations of nuclei with non-zero spin, and transforms to a square-root dependence at high concentrations. It is shown that the behavior depends on the distribution of spin density around the paramagnetic center. The results of the numerical approach are confirmed by a theoretical analysis using computations of resonance line moments.

The active site of the [FeFe]-hydrogenase from Desulfovibrio desulfuricans. I. Light sensitivity and magnetic hyperfine interactions as observed by electron paramagnetic resonance

The hydrogen-activating cluster (H cluster) in [FeFe]-hydrogenases consists of two moieties. The [2Fe]H subcluster is a (L)(CO)(CN)Fe(mu-RS2)(mu-CO)Fe(CysS)(CO)(CN) centre. The Cys-bound Fe is called Fe1, the other iron Fe2. The Cys-thiol forms a bridge to a [4Fe-4S] cluster, the [4Fe-4S]H subcluster. We report that electron paramagnetic resonance (EPR) spectra of the 57Fe-enriched enzyme from Desulfovibrio desulfuricans in the H(ox)-CO state are consistent with a magnetic hyperfine interaction of the unpaired spin with all six Fe atoms of the H cluster. In contrast to the inactive aerobic enzyme, the active enzyme is easily destroyed by light. The [2Fe]H subcluster in some enzyme molecules loses CO by photolysis, whereupon other molecules firmly bind the released CO to form the H(ox)-CO state giving rise to the so-called axial 2.06 EPR signal. Though not destroyed by light, the H(ox)-CO state is affected by it. As demonstrated in the accompanying paper [49] two of the intrinsic COs, both bound to Fe2, can be exchanged by extrinsic 13CO during illumination at 2 degrees C. We found that only one of the three 13COs, the one at the extrinsic position, gives an EPR-detectable isotropic superhyperfine interaction of 0.6 mT. At 30 K both the inhibiting extrinsic CO bound to Fe2 and one more CO can be photolysed. EPR spectra of the photolysed products are consistent with a 3d7 system of Fe with the formal oxidation state +1. The damaged enzyme shows a light-sensitive g = 5 signal which is ascribed to an S = 3/2 form of the [2Fe](H) subcluster. The light sensitivity of the enzyme explains the occurrence of the g = 5 signal and the axial 2.06 signal in published EPR spectra of nearly all preparations studied thus far.

Investigations on the Hyperfine and Superhyperfine Interaction Parameters for Cs2GeF6:Mn4+

The hyperfine structure constant A and the superhyperfine interaction parameters Aʹ and Bʹ of Cs2GeF6:Mn4+ are theoretically studied by the cluster approach. The orbital mixing coefficients and the unpaired spin densities in 2s, 2pσ and 2pπ fluorine orbitals are obtained from the optical spectra and the impurity-ligand distance of the studied system. Based on a uniform scheme, the parameters A, Aʹ and Bʹ (as well as the g factor) are reasonably explained. The results are discussed, and the unpaired spin densities of the 2s, 2pσ and 2pπ orbitals of the ligand F− are compared with those in previous works.

The microscopic structure of the oxygen–aluminium hole center in natural and neutron irradiated blue topaz

The dominant O− hole center in natural and neutron irradiated blue topaz with general formula Al2SiO4(F,OH)2 has been investigated with electron paramagnetic resonance (EPR) and optical absorption. The analysis of the EPR spectra of the O− center yielded superhyperfine interactions with two equivalent Al neighbors in four magnetically inequivalent positions. From the g-factors it is found that the O− hole center is located in (8d) Wyckoff positions on fluoride sites that were substituted by hydroxyl molecules prior to the irradiation. The spin Hamiltonian parameters were successfully interpreted with the model of transferred hyperfine interaction by exchange polarization supporting the localization of O− in (F,OH)− sites. The O− center has the same thermal stability as the absorption band centered at 620 nm, which is responsible for the blue color. The intensity of the absorption band correlates linearly with the O− concentration. Its correlation with the blue color is discussed.

Electron paramagnetic resonance study ofZnAl2S4 spinel

Single crystals of ZnAl2S4 spineldoped by paramagnetic Cr3+ and Mn2+ ions have been studied by the electron paramagnetic resonance (EPR) technique. Thecrystal field symmetry around the impurity ions has been determined from theangular behaviour of X-band EPR spectra. The anisotropic EPR signal of theCr3+ ions shows splitting into 31 narrow lines due to the super-hyperfine interaction betweenunpaired electron spins of the chromium centres and nuclear spins of six neighbouringAl27 (I = 5/2) ions. It has beenestablished that the Cr3+ ions are located at the octahedral sites in the spinel structure, and the super-hyperfineinteraction results from a weak covalent bounding with the Al atoms. The EPR signals of theCr3+ paramagnetic centres show no fine-structure splitting due to a perfectlycubic symmetry of the local crystal field in the octahedral sites of theZnAl2S4 spinel structure. A weak EPR signal consisting of six componentshas been ascribed to the transitions between hyperfine levels of theMn2+ (I = 5/2,S = 5/2) ions located at tetrahedral sites, while the fine-structure splitting of eachcomponent could be resolved only for special orientations of the sample in theexternal magnetic field. The parameters of the EPR signal of both chromiumand manganese centres indicate that there is an essential covalence in theZnAl2S4 spinel crystal. Verynarrow linewidths (∼2 Oe) of the Cr3+ EPR signal components point to very high homogeneity and quality of theZnAl2S4 crystals.

Interface Defects in n-Type 3C-SiC/SiO<sub>2</sub>: An EPR Study of Oxidized Porous Silicon Carbide Single Crystals

The defects at the 3C-SiC/SiO2 interface have been studied by X-band EPR spectroscopy in oxidized porous 3C-SiC. One interface defect is detected; its spin Hamiltonian parameters, spin S=1/2, C3V symmetry, g//=2.00238 and g⊥=2.00317, central hyperfine interaction (CHF) with one carbon atom and AB//[001]=48G and superhyperfine (SHF) interaction with three equivalent Si neighbour atoms and TB//[001]=12.4G, allow us to attribute the center to a sp3 coordinated carbon dangling bond center, PbC.

SURFACE MORPHOLOGY OF SUBMICRON CRYSTALS IN ALUMINUM NITRIDE FILMS GROWN BY DC MAGNETRON SPUTTERING

Aluminium nitride (AlN) thin films were fabricated on a glass substrate by reactive magnetron sputtering. Raman microscopy was then employed to follow the characteristics of their optical and acoustic phonon modes. At the optimal sputtering time of 30 minutes, the defect-induced first and second order Raman spectra were observed in 400–800 cm-1 band which were mostly related to the coating compositions. However, at the 30-, 60- and 90-minute sputtering, crystals of submicron size order of AlN were achieved. This could be clearly identified by the presence of Raman peak at 658–662 cm-1. Powder X-ray diffraction (PXRD) patterns revealed the development of (002) and (101) planes of hexagonal wurtzite AlN phase. The optimal average grain size measured by atomic force microscopy (AFM) is at 330 nm. It was found that the hardness was strongly dependent on roughness of the film, the maximum of which was achieved at 20.00 GPa. The presence of F-type defects in AlN films was investigated by X-band (~9.44 GHz) ESR spectrometer at 295 K. The ESR experiments were carried out by applying magnetic field perpendicular to AlN film, which showed the ESR six-peak multiplet signal at ~290 mT arising from superhyperfine interactions between nuclear spin I = 5/2 of 27 Al and electron spins trapped in nitrogen vacancies. The ESR signals are simulated and the ESR parameters are calculated. The vacancies are clearly randomly distributed as the ESR signals are independent of rotation angle (φ) about the normal of the film. All these results were analyzed and presented as a function of the deposition parameters and composition, and crystalline phases existed in the films.