- C-axis oriented Ba-ferrite thin film with small grain for perpendicular magnetic recording
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Hexagonal Ba-ferrite(BaM) thin films with amorphous AlO(a-AlO) under-layer were prepared by a facing targets sputtering system. The grain size of c-axis perpendicularly oriented BaM/a-AlO films is about 20 nm at the thickness of 20 nm for BaM layer. The perpendicular coercivity is about 3.5-4.3 kOe with BaM layer thickness in the range from 80 to 30 nm and 2.3 kOe for BaM layer thickness of 20 nm.The in-plane coercivity for BaM/a-AlO films was less than 0. 1 kOe at the thickness ranging from 20 to 80 nm.
- Morisako,Shams,Miura,Matsumoto,Gee,Park,Hong
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- Reactivities of spin-orbit states in Al((2)P(1/2,3/2))+O2(X(3)Σ(-)(g))AlO(X(2)Σ(+))+O((3)P(0,1,2)). A fluorescence imaging study
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A crossed beam chemical reaction, Al((2)P(1/2,3/2))+O2(X(3)Σ(-)(g)) AlO(X(2)Σ(+))+O((3)P(0,1,2)) was investigated by fluorescence imaging techniques. Multiplex detection of speeds and quantum states of both reactants and products has been implemented. The
- Chen, Kuo-mei,Sung, Chun-hwa,Chang, Jia-lin,Chung, Teng-hui,Lee, Kuo-huei
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- Detection of O (3PJ) atoms formed by reaction, Al+ O2 → AlO+O under crossed-beam condition
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The vacuum ultraviolet laser-induced fluorescence technique was employed to detect the oxygen atoms formed by the reaction, Al+ O2 → AlO+O. The measurements were carried out under the crossed-beam condition at 12.2 kJmol of collision energy. The relative
- Ishida, Masayuki,Higashiyama, Tomohiko,Matsumoto, Yoshiteru,Honma, Kenji
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- High-contrast top-emitting organic light-emitting diodes with AlO1.086 dark-and-conductive electrodes
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To improve the poor contrast of conventional organic light-emitting diodes (OLEDs) resulting from highly reflective metal electrode, a dark-and-conductive electrode with an average reflectance of 28.1% and a resistivity of 4.6 × 10-4 Ω/cm was fabricated by fine-tuning O2/Ar flow ratio on aluminum electrode sputtering. X-ray photoelectron spectroscopy analysis indicates pure aluminum and aluminum oxide coexist in the fabricated dark-and-conductive electrodes. With the proposed dark-and-conductive AlO1.086 electrodes, top-emitting OLEDs exhibit significantly improved contrast, whereas maintain moderate luminous efficiency. The demonstrated AlO1.086 dark-and-conductive electrodes can potentially replace the circular polarizers for high-contrast OLED display applications.
- Chen, Shuming,Yu, Jianning
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- Crossed-beam study of the Al( 2P1/2, 3/2 )+O2( X 3Σ-g ) → AlO( X 2Σ+ )+O( 3PJ ) reaction at low and very low kinetic energies
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The title reaction is revisited at kinetic energies between 255 and 6 meV with a new crossed-beam apparatus. The AlO dissociation energy is evaluated to be D0(AlO)=5.27±0.01 eV. Al(2P1/2) and Al(2P3/2) spin-orbit reactivities are shown to be different. The relative cross-section of Al(2P1/2)+O2 is found to increase monotonically when decreasing kinetic energy. The variation of the calculated thermal rate constant is in agreement with kinetic measurements performed between 1083 and 23 K. Good agreement is also found with theoretical treatment based on the adiabatic capture centrifugal sudden approximation.
- Naulin, Christian,Costes, Michel
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- Electronic transition moment of the AlO(B(2)Σ(+)-X(2)Σ(+)) emission. Analysis of the R dependence of the Al(2+)O(2-) character in the X(2)Σ(+) state
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The dependence of the electronic transition moment, R(e)(R), of the AlO(B(2)Σ(+)-X(2)Σ(+)) system on the internuclear distance, R, has been determined by an analysis of the intensity distribution of the emission spectra as R(e)(R)=[1-2.29(13)(R/?-1.5)**2]
- Sato, Noriko,Ito, Haruhiko,Kuchitsu, Kozo
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- Kinetics of the Reaction Al(2PO) + H2O over an Extended Temperature Range
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The temperature dependence of the reaction Al(2PK0) + H2O has been investigated over the temperature range 298-1174 K.Aluminium atoms were produced by photodissociation of Al(C2H5)3 and were detected by laser-induced fluorescence.Non
- McClean, Roy E.,Nelson, H. M.,Campbell, Mark L.
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- Kinetic energy dependence of Al+ + O2 -> AlO+ + O
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The endothermic reaction of Al+ with O2 is studied using a guided ion-beam apparatus.The reaction cross section is measured as a function of kinetic energy from 0 to 20 eV.The threshold energy for the reaction, E0, is determined from an empirical model to be 3.64+/-0.04 eV.Phase space calculations of the cross section performed with E0 as the only adjustable parameter yield a similar result, E0 = 3.60+/-0.02 eV, and predict the absolute magnitude of the reaction cross section within experimental error.We conservatively quote the threshold energy as 3.62+/-0.12 eV which is somewhat higher than the thermodynamic threshold calculated using literature thermochemistry, 3.40+/-0.16 eV.This may indicate that a slight barrier to the reaction exists, or that AlO+ is produced in an excited state, or that the literature thermochemistry needs revision.Our results suggest D00(AlO+)1.50+/-0.12 eV and I.P. (AlO) 9.75+/-0.13 eV.
- Weber, M. E.,Elkind, J. L.,Armentrout, P. B.
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- MICROSTRUCTURE DEVELOPMENT OF ALUMINUM OXIDE - GRAPHITE MIXTURE DURING CARBOTHERMIC REDUCTION.
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Reactions in the system Al-O-C are discussed. The development of the unique composite microstructure is attributed to reactions which serve to coarsen internal grains by vapor-phase transport of volatile aluminum suboxides and, thereby, reduce firing shri
- Klug,Pasco,Borom
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- Pressure and Temperature Dependence of the Kinetics of the Reaction Al + CO2
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We measured the pressure and temperature dependence of the rate constants of the reaction of Al + CO2 between 10 and 600 Torr total pressure and 298 and 1215 K in our high-temperature reactor.The Al atoms were generated by the 248-nm photolysis of Al(CH3)3 and probed by laser-induced fluorescence.Below 700 K, the rate constants show a strong pressure dependence suggesting that the reaction is proceeding through a complex formation mechanism with some decomposition of the complex to the products AlO and CO.Above 700 K, the observed rate constants are pressure independent, indicating that a direct abstraction channel becomes dominant.An Arrhenius fit to the rate constants measured in this high-temperature regime results in a preexponential factor of (2.9 +/- 0.7) * 10-10 cm3 s-1 and an activation energy of 6.4 +/- 0.4 kcal mol-1.
- Garland, Nancy L.,Douglass, C. H.,Nelson, H. H.
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- Reaction dynamics of Al+O2→AlO+O studied by the crossed-beam laser-induced fluorescence technique
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A study was performed on the reaction dynamics of Al+O 2→AlO+O. The crossed-beam technique at five collision energies from 6.9 to 25.3 kJ/mol was used for the purpose. The laser-induced fluorescence technique was used for the detection of product AlO. The determination of the rotational-vibrational distributions was also discussed.
- Honma, Kenji
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- Reaction of aluminum cluster ions with oxygen and nitrous oxide: Energetics and dynamics of cluster oxidation
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We report a study of the absolute cross sections, reaction threshold energies, and product branching ratios for interactions of aluminum cluster ions (Al+n, n = 1-9) with O2 and N2O.Most of the reactions are observed to have collision energy thresholds which are attributed to activation barriers or bottlenecks.At collision energies above threshold, exoergic oxidation of the cluster ions occurs, and the resulting energy release causes extensive fragmentation to yield a variety of product ions.Comparison of threshold behavior for different product channels suggests that in addition to the dominant oxidation reactions, the clusters undergo Al abstraction, O2-Al+ exchange, and collision induced dissociation.
- Ruatta, Stephen A.,Anderson, Scott L.
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- Formation and Oxidation of Metal-Based CO and CO2 Complexes: Characterization of Al(CO)x and Al(CO2)x and their Oxidation
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In a comparative study, aluminum atoms entrained in argon, CO, and CO2 are oxidized with ozone to inspect the nature of aluminum complexation with CO and CO2 to form Al(CO)x (x= 1, 2) and AlCO2 adducts.The optical signatures corresponding to the chemiluminescent oxidation of these complexes with ozone to form the AlO B2Σ+ state or, in the case of CO2, a polyatomic complex are compared to that AlO B2Σ+ emission associated with the chemiluminescent oxidation of nonbonded aluminum atoms in argon.We (1) establish a method for evaluating M(CO)x binding energies and (2) observe the optical signature for a potentially long-lived (ca. 1E-7 s) metal oxide-carbon dioxide solvation complex formed in metal-CO2 complex oxidation.From a comparison of these studies, with results obtained for Al-N2O oxidation, we estimate a lower bound to the total (Al(CO)2 binding energy (to Al+2CO) of ca.0.7 eV.The current study in conjunction with parallel efforts involving the transition metals suggests a method for studying the spectra of MCO, M(CO)2, and M-CO2 complexes.
- McQuaid, M.,Woodward J. R.,Gole, J. L.
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- Vaporization of aluminum oxide in neutral and reductive conditions
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High-temperature mass spectrometry was used to study vaporization of aluminum oxide in neutral and reductive (carbon-containing medium) conditions. The reduction of Al2O3 with carbon occurs primarily through the gas phase.
- Folomeikin,Lopatin,Stolyarova
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- Role of Al-O2 chemistry in the laser-induced vaporization of Al films in air
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Evidence for the prominent role of atypical reactions, and enhanced vaporization arising from resonant optical absorption of the exciting beam, in the pulsed-laser heating of thin films is presented. Time-resolved emission of Al and the reaction product A
- Pangilinan,Russell
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- Gas-Phase Reactions of AlO with Small Molecules
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AlO is produced in the gas phase at 296 K by reaction of Al atoms with N2O following Al atom formation by multiphoton dissociation of trimethylaluminium (TMA).Production and decay of Al and AlO are monitored by laser-induced fluorescence.The combination of efficient vibrational relaxation of AlO by N2O and low reactivity of AlO with N2O at room temperature allows studies of AlO reaction kinetics to be carried out with a range of molecules using N2O as a buffer gas.Second-order rate constants at 296 K (cm3 molecule-1 s-1) are reported for the reactions of ground-state Al(32PJ) with N2O, (1.1+/-0.1)*10-11; ethylene oxide, (1.3+/-0.1)*10-10, and TMA, (1.3+/-0.3)*10-10 in Ar buffer gas, and for reactions of ground-state AlO(X2Σ+,v=0) with ethylene oxide, (2.1+/-0.5)*10-10; tetramethylethylene, (1.1+/-0.4)*10-11; and TMA, (3.0+/-1.0)*10-10 in N2O buffer gas.A third-order rate constant of (4.3+/-0.4)*10-32 cm6 molecule-2 s-1 is reported for the AlO+CO association reaction in N2O buffer gas.Reactions of AlO with CO2 and C2H4 showed buffer gas pressure dependent pseudo-second-order rate constants, indicative of processes involving formation of association complexes.Estimate are made of the upper limits for the rate constants for reaction of AlO with N2O, methane, molecular hydrogen, isobutane, benzene, toulene, CF3Cl, CF3Br, and CCl4, for which the reaction rates at 296 K were negligible.
- Parnis, J. Mark,Mitchell, S. A.,Kanigan, Tanya S.,Hackett, Peter A.
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- Experimental and theoretical kinetics for the reaction of Al with O2 at temperatures between 23 and 295 K
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The first study of the kinetics of Al atoms with O2 at low and ultralow temperatures is reported. Rate constants have been measured from 295 to 23 K using the pulsed laser photolysis-laser-induced fluorescence (PLP-LIF) technique in a CRESU (Cinetique de Reaction en Ecoulement Supersonique Uniforme) apparatus. Rate constants were found to increase monotonically with decreasing temperature: k(T) = (1.75 ± 0.10) × 10-10(T/298)-0.25±0.02 exp[(7.3 ± 3.0)/T] cm3 s-1. The rate constant for the reaction Al with O2 has also been calculated as a function of temperature using a theoretical approach based on the adiabatic capture centrifugal sudden approximation (ACCSA) method. These calculations were found to be in good agreement with experimental results and were able to explain the observed temperature dependence by the open-shell nature of the reactants. Possible astrophysical implications are also discussed concerning the chemistry of aluminum atoms in the interstellar medium.
- Le Picard,Canosa,Travers,Chastaing,Rowe,Stoecklin
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- Spectroscopic studies of AlO in argon matrices
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The diatomic species AlO has been isolated in argon at 18 K as an Al + O2 reaction product and shown to produce intense laser induced fluorescence in the visible.An infrered-optical double resonance experiment has established the X state vibrational fundamental at 975 cm-1, one of four possibilities previously proposed from infrared studies. 18O experiments further establish the assignment.The apparent low infrared intensity of the AlO stretch is consistent with a recent ab initio calculation of an oscillator strenght of 4*10-7.This anomalously low value is confirmed by comparison of infrared and visible absorption intensities for similar samples.A v = 1 lifetime in excess of 6 ms was directly measured for AlO by the double resonance method.This slow rate of radiative relaxation makes AlO attractive as a probe molecule for vibrational relaxation studies.
- Bares, S. J.,Haak, M.,Nibler, J. W.
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- Oxidation of Transition-Metal Cations in the Gas Phase. Oxigen Bond Dissociation Energies and Formation of an Excited-State Product
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Gas-phase studies of oxigen atom transfer fro various oxidants to transition-metal cations by ion cyclotron resonance spectroscopy are reported.Observation of these reactions is used to establish upper and lower limits for metal oxide-cation bond dissociation energies, D(M+-O).For MgO+, AlO+, MnO+, CoO+, NiO+, CuO+, and ZnO+ the results bracket D(M+-O) between D(O2-O)=25.5 kcal/mol and D(N2-O)=40.0 kcal/mol.For V+ and Fe+ the results also bracket the bond energy in relatively narrow ranges: D(V+-O)=135+/-16 kcal/mol and D(Fe+-O)=101+/-18 kcal/mol.New upper and/or lower limits are established for some of the other metal cation studied.The VO+ produced by reaction of V+ with N2O reacts with H2 or CH4 to give VOH+.However, when VO+ is produced by reaction of V+ with O2, D(O-O)=119.2 kcal/mol, reaction to give VOH+ does not occur.These results suggest that the VO+ product of the reaction of V+ and N2O is an excited-state species with a lifetime at least as long as the reaction time which is as long as about 150 ms in these experiments.Similar behavior is seen with TiO+.
- Kappes, Manfred M.,Staley, Ralph H.
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- Catalytic system and process for the production of hydrogen
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Catalytic system for the production of hydrogen consisting of an active component based on iron and a micro-spheroidal carrier based on alumina and represented by the following formula [Fex1Mx2Qx3Dx4Alx5]Oy wherein xi with i=1.5 represent the atomic percentages assuming values which satisfy the equation Σxi=100. y is the value required by the oxidation number with which the components are present in the formulate, x1 is the atomic percentage with which Fe is present in the formulate and ranges from 5 to 80, preferably from 20 to 50, M is Cr and/or Mn, x2 ranges from 0 to 30, preferably from 0 to 10, Q is La, Lanthanides (with Ce particularly preferred), Zr or a combination thereof, x3 ranges from 0 to 30, preferably from 0 to 10, D is Mg, Ca, Ba, Co, Ni, Cu, Zn or combinations thereof, x4 ranges from 0 to 35, preferably from 5 to 25, x5 is the atomic percentage with which Al is present in the formulate and ranges from 20 to 95, preferably from 50 to 80.
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Page 8; 9; 10
(2008/06/13)
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- Electron spin resonance matrix isolation studies of 27Al16,17O, 69,71Ga16,17O and 115In16,17O: Observed hyperfine interactions compared with ab initio theoretical results
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Electron spin resonance (ESR) studies are reported for Al16,17O, Ga16,17O, and In16,17O isolated in neon matrices at 4 K. Except for Al16O, no previous ESR measurements have been reported for these X 2Σ diatomic radicals. The pulsed laser vaporization of the metals in the presence of 16O2 and 17O2 produced high quality ESR spectra of these metal oxide radicals whose nuclear hyperfine interactions (A tensors) were fully resolved for both the metal and oxygen nuclei. An analysis of the experimental spin densities in combination with different types of theoretical calculations provided detailed information concerning the electronic structure trends going down this metal oxide group. Increased p-orbital spin density on oxygen was observed for the heavier metal oxide radicals. Nonrelativistic ab initio calculations with an extended basis set and the UB3LYP method reproduced the trends in the isotropic and dipolar hyperfine interactions. All-electron CI calculations, restricted open-shell Hartree-Fock (ROHF) wave functions, and unrestricted Hartree-Fock wave functions gave results very different from experiment and from each other for the isotropic interaction. All calculations were in fair agreement with each other for the dipolar interaction and provided an assignment of the sign for that term.
- Knight Jr., Lon B.,Kirk, Thomas J.,Herlong, John,Kaup, John G.,Davidson
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p. 7011 - 7019
(2007/10/03)
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- Reactions of Pulsed-Laser Evaporated Aluminium Atoms with Oxygen. Infrared Spectra of the Reaction Products in Solid Argon
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Reactions of pulsed-laser evaporated Al atoms with O2 in a condensing argon stream gave cyclic-AlO2 at 496.3 cm-1 as the major product.In addition sharp new absorptions at 1211.2, 1176.3, and 1129.5 cm-1 are identified on the basis of isotopic shifts and multiplets as linear OAlOAlO, AlOAlO, and OAlO, respectively.The identification of linear OAlOAlO and AlOAlO was confirmed by MP2 calculations of isotopic frequencies.The 1129.5 cm-1 band exhibited a sharp mixed oxygen isotopic triplet and isotopic ratio 1.0261 in agreement with that expected for a linear molecule.A sharp 1092.5 cm-1 absorption is identified as OAlOO on the basis of a mixed oxygen isotopic quartet with 16O2/16O18O/18O2 and 16O2/18O2 reagent mixtures.The only AlO2 isomers observed were the cyclic and linear forms found by theory to be potential minima.The observation of isotopic shifts and mixed isotopic multiplets is absolutely essential for the identification of new transient species.
- Andrews, Lester,Burkholder, Thomas R.,Yustein, Jason T.
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p. 10182 - 10189
(2007/10/02)
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- Raman spectra of the products of the Al + O2 reaction in inert matrices. Possible structure of the Al2O3 molecule
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We have obtained the Raman spectra of the molecules produced by the interaction of Al with O2 in argon and in nitrogen matrices.In the spectra for the Ar matrices we observed bands assigned to totally symmetric vibrations of the Al2O and Al(O2)(cycl.) molecules, and of various polymers of composition (AlO)n.In the spectra for the nitrogen matrices a doublet at 1031, 1024 cm-1 assigned to ν1 of the Al2O3 molecule, is additionally observed.By comparing these results with the i.r. spectra of the system we have calculated the force field of the Al2O3 molecule and we have proposed a model of its structure.
- Rozhanskii, I. L.,Serebrennikov, L. V.,Shevel'kov, A. F.
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p. 276 - 277
(2007/10/02)
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- A High-Temperature Fast-Flow-Reactor Kinetics Study of the Reaction AlO + CO2 -> AlO2 + CO. Thermochemical Implications
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The title reaction has been studied in a high-temperature fast-flow reactor (HTFFR) at temperatures from 500 to 1300 K.Laser-induced fluorescence was used to monitor relative . k(T) was determined to be (2.5 +/- 1.3) * 10-14 exp cm3 molecule-1 s-1 (confidence level > 95percent).The reaction probably proceeds via an intermediate complex which preferentially dissociates to the reactants.The negative activation energy implies D(O-AlO) >/= D(O-CO) = 127 kcal mol-1, which is incompatible with the O-AlO dissociation energy obtained for AlO2 from Al2O3 evaporation-mass spectrometry studies.It is argued that the latter AlO2 may have a different structure from that of the present work.
- Rogowski, Donald F.,English, Andrew J.,Fontijn, Arthur
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p. 1688 - 1691
(2007/10/02)
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- MATRIX-ISOLATION STUDIES BY ELECTRONIC SPECTROSCOPY OF GROUP IIIA METAL-WATER PHOTOCHEMISTRY
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This paper reports an investigation of the electronic structures of the Group IIIA metal atom hydration reaction intermediates (MOH2 adducts) and their subsequent photolysis products (HMOH, MOH and MO) where M = Al, Ga and In.The metal-water interaction in the adduct is sufficiently strong to perturb the electronic structure of the metal atom; consequently, one observes a unique band structure for the adduct that is red shifted from the metal's atomic resonance transition.Molecular orbital and electronic state-to-state correlations are presented.
- Douglas, Monte A.,Hauge, Robert H.,Margrave, John L.
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p. 1533 - 1554
(2007/10/02)
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