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The conductivity and the conductivity relaxation of x[Ag.sub.2]O-(1-x)Mo[O.sub.3] glasses with varying [Ag.sub.2]O content are studied in wide frequency and temperature ranges. The conductivity and the activation energy of these glasses are compared with other glasses where the silver molybdate glasses exhibit the highest conductivity and the lowest activation energy.

Several new polyamidate-linked dimolyhdenum compounds, prepared in good yield and high purity by direct assembly of M[O.sub.2][[DAniF].sub.3]([O.sub.2]CC[H.sub.3]) are reported with polyamides in the presence of strong base [H.sup.-]. It is suggested that M[O.sub.2.sup.5+] is an electron-trapped species with one electron residing on each of the two dimolybdenum units as revealed by electrochemical measurements.

A procedure is described that allows the total charge state of a complex molecule to be obtained from its redox potential data by comparison with good data for chemically similar reference compounds, the link made by the calculated energies of the Fermi level or highest occupied molecular orbital (HOMO). This method is used to determine the resting redox state of the FeMo cofactor, FeMo-co, which must be protonated in its resting state if the atom at the center is C rather than N.

A novel dual-metal gate technology that uses a combination of Mo-Mo[Si.sub.x] gate electrodes is proposed. On the SiO2 gate dielectric, Mo-Mo[Si.sub.x] combination could be appropriate not only for devices with advanced transistor structures but also for conventional bulk devices if arsenic preimplantation is adopted.

Explorations of the reactivity of Fe/Mo/S clusters of some relevance to the FeMoco nitrogenase has led to new double-fused cubane clusters with the Mo2Fe6S8 core as derivatives of the known (Cl4-cat)2Mo2Fe6S8(PPr3)6 (l) fused double cubane. New clusters are obtained by substitution reactions of the PPr3 ligands with Cl(super -), BH4(super -) and N3(super -).

Thin films of Sr2FeMoO6 (SFMO) are grown epitaxially on (001) SrTiO3 substrates by pulsed laser deposition and the effects of the strain relaxation on the electronic properties of SFMO are determined. Ab initio calculations suggest that the variation of SFMO lattice parameters due to strain has a limited impact on the magnetization, and SFMO is half metallic only for thickness above 44 nm.

A fully functioning programmable voltage standard chips with double- and triple-stacked MoSi2 barrier Josephson junctions with over 100,000 junctions operating simultaneously on a 1cm x 1 cm chip are presented. The maximum output voltages of the double- and triple-stacked chips are 2.6 V and 3.9 V, with respective operating current margins of 2 mA and 1 mA.

Stacking enables the junctions to be packed more densely thus increasing design flexibility and margins for the microwave circuits. The measurements from two- and three- junction stacks for application to ac Josephson voltage standards of circuits having MoSi2 barriers is presented.

Tall, uniform stacked Josephson junction arrays are made by developing an etch process using an inductively coupled plasma etcher. Dc and microwave electrical characteristics of distributed and lumped arrays and the technological improvements needed to fabricate lumped arrays for voltage-standard applications are described.

A combinatorial rf magnetron sputter deposition technique was employed to investigate the electrical characteristics and microstructural properties of molybdenum tungsten (MoW) high temperature electrodes as a function of the binary composition. The effect of substrate bias and temperature was investigated.

The single crystalline PbMoO4 dendrites were prepared by a simple hydrothermal method in the presence of surfactants. The formation and evolution of dendrites was investigated by transmission electron microscopy, and the results showed that the dendritic structure was achieved through oriented attachment of nanoparticles along crystallographically specific direction.

The compounds ((super t)BuCO2)3M2(mu-O2CCO2)M2(O2C(super t)Bu)3(M4OXA), where M=Mo or W, are shown by analysis of powder X-ray diffraction data to have extended lattice structures wherein oxygen atoms from the oxalate and pivalate ligands of one M4OXA molecule are linked to metal atoms of neighboring molecules. The Raman, resonance Raman, and variable-temperature electronic spectra of these oxalate-linked 'dimers of dimers' reveal the richness of orbital mixing in these extended pi systems, both in the ground and excited states.

A simple method was developed for the synthesis of amides by molybdenum-mediated carbamoylation of aryl halides. Mo-mediated carbamoylation reaction which requires only a slight excess amount of carbon monoxide in the form of its molybdenum complex, Mo[(CO).sub.6] could also be applied for the synthesis of a wide variety of secondary and tertiary amides as well as primary amides by using aqueous ammonia.

Magnetic structure and dielectric response of [Ca.sub.3]CoMo[O.sub.6] are analyzed as a function of temperature and applied magnetic field. Dielectric measurements have disclosed the presence of magnetoelectric coupling below magnetic ordering temperature and have described the existence of a correlation between magnetic structure and dielectric properties.

Carrier lifetime measurements are carried out on molybdenum-contaminated silicon by using a temperature controlled photoconductance instrument. The studies have shown that a projection of electrons to higher temperature has suggested the defect to have energy of 0.375 eV above the valence band edge of silicon.

A study was conducted to determine the structural, electrical, and magnetic properties of the undoped and Fe doped molybdenum oxide thin films on c-plane or sapphire substrate grown by using pulsed laser ablation. The results provided insight into films orientation in the (100) direction, monoclinic structure based on Mo[O.sub.2] phase, chemical state of Fe, and ferromagnetic behavior of Fe doped samples at room temperature.

The synthesis, X-ray structure and EPR spectra of paramagnetic Mo(V) [d.sup.1] borohydride complex Mo[(NAr).sub.2][(P[Me.sub.3]).sub.2]([[eta].sup.2]-B[H.sub.4]) are described. Density functional theory calculations are used for determining the electronic structure and bonding parameters of the complex.

Two neutral compounds with [Mo.sub.2] units linked by squarate dianions, [[Mo.sub.2][(DAniF)].sub.3],sub.2([mu.sub.4]-[C.sub.4][O.sub.4]) and [[Mo.sub.2][(DmC[F.sub.3]F)].sub.3].sub.2([mu.sub.4]-[C.sub.4][O.sub.4]) are synthesized and structurally studied. Electrochemistry of the two neutral compounds shows weak electronic interactions between the two molybdenum units that reduces antiaromaticity in the central [C.sub.4] ring.

Density functional theory and coupled cluster theory are used for studying the structures and energetics of the low-lying electronic states of [M.sub.3][O.sub.9.sup.-] and [M.sub.3][O.sub.9.sup.2-], where M = Mo, W. The adiabatic and vertical electron detachment energies (ADEs and VDEs) of the anionic clusters are calculated.

A comparative study of the modulating electronic coupling observed in the compounds having two dimolybednum units using oxygen and sulfur donor links is presented. The analysis reveals that the coupling highly enhances on changing the oxygen atoms to the sulfur atoms.

The phosphinidene complex is shown to have different Mo-P bonds and has displayed a high reactivity located at the short Mo-P bond. The analysis has shown that the P atoms have displayed an unprecedented trigonal-pyramidal-like environment, instead of the expected tetrahedral distribution of bonds.

A morphological and spectroscopic-impedance characterization of W[O.sub.3] and Mo[O.sub.3]-W[O.sub.3] mixed oxide screen printed on alumina substrates is presented. Mo[O.sub.3]-W[O.sub.3] has shown a monodispersed distribution of grains and the resistance variations are expected to be in the sub-parts per million (ppm) range.

The structural, energetic, spectroscopic, electronic and bonding properties of [[[Mo.sub.3]Cu[S.sub.4][(dmpe).sub.3][Cl.sub.4]].sup.+] and [Mo.sub.3]Ni[Si.sub.4][(dmpe).sub.3][Cl.sub.4] with 16 metal clusters, where dmpe = 1,2-bis(dimethylphosphino)ethane, are analyzed. The electronic delocalization present in these cluster complexes are attributed to the metal formal oxidation states.

A set of new [W[S.sub.4][Cu.sub.4]]- or [MoO[S.sub.3][Cu.sub.3]-based supramolecular assemblies are prepared from reactions of preformed cluster compounds [[[Et.sub.4]N].sub.4][W[S.sub.4][Cu.sub.4][I.sub.6]] and [[[(n-Bu).sub.4]N].sub.2][MoO[S.sub.3][Cu.sub.3][X.sub.3] (X = I, SCN) with flexible ditopic ligands. The results have provided new routes to the rational design and construction of complicated cluster-based supramolecular arrays.

The synthesis of the first symmetrically bridged and quadruply bonded dinuclear Mo(II) amido complex of the type of [M.sub.2][X.sub.4] (where M = Mo or W) is reported. Complex [Mo.sub.2][[mu]-[[eta].sup.2]-[Me.sub.2]Si[(NDipp).sub.2]].sub.2] has displayed an electronic structure that is different from the conventional paddlewheeled structures.

The reaction of the edge-bridged double cubane cluster [[(Tp).sub.2][M.sub.2][Fe.sub.6][S.sub.8][(P[Et.sub.3]).sub.4]] (Tp = hydrotris(pyrazolyl)borate(1-)) with hydrosulfide has afforded the [P.sup.N]-type [Mo.sub.2][Fe.sub.6][S.sub.9] cluster. The analysis has shown that edge-bridged double cubane clusters are highly effective precursors for the synthesis of molecules with the [P.sup.N] cluster topology by the process of core conversion.

An investigation of the kinetics of the reaction of [Mo.sup.VI]{[S.sub.2][C.sub.6][H.sub.4]}[.sub.3] with organic phosphines to produce the anionic Mo(V) complex, [Mo.sup.VI]{[S.sub.2][C.sub.6][H.sub.4]}[.sub.3][.sup.-], and phosphine oxide is presented. Oxygen isotope tracing confirms that water rather than dioxygen is the source of the oxygen atom which is transferred to the phosphine, a reactivity which parallels oxidase activity of xanthine enzyme with phosphine as oxygen atom acceptor and [Mo.sup.VI]{[S.sub.2][C.sub.6][H.sub.4]}[.sub.3] as electron acceptor.

Density functional calculations are performed on M2X6 complexes (where M=U,W, and Mo and X=Cl,F,OH,NH2, and CH3) to investigate general aspects of their electronic structures and explore the similarities and differences in metal-metal bonding between f-block and d-block elements. Multiple (sigma and pi) bonding is predicted for all species investigated, with predominant f-f and d-d metal orbital character, respectively, for U and W or Mo complexes.

The qualitative and quantitative insights into the exchange interaction involving 4d or 5d metal ions in cyano-bridged complexes are reported. Both the experimental and the calculated behaviors have revealed a noticeable difference between the Mo and the W derivatives that are correlated to the spin densities transferred by these metal ions onto the bridging cyano ligands.

Tetranuclear Mo4 clusters with two quadruply bonded [Mo2.sup.4+] units, [Mo2(cis-DAniF)2] (DAniF = N,N'-di-p-anisylformamidinate), linked by alkoxides are prepared and the nonbonding separation between the midpoints of the quadruply bonded units is the shortest among compounds having two linked [Mo2.sup.4+] units. There is a decrease of the dimetal separation that suggests bond formation between dimetal centers, which reduces the bond order between the metal atoms in the species that initially had a quadruple bond.

The adsorption of [C.sub.3] hydrocarbons propylene, 1-iodopropane, and 1,3-diiodopropane is studied in ultrahigh vacuum on a molybdenum-aluminium alloy formed by molybdenum hexacarbonyl reaction with a planar alumina film growth on a Mo(100) substrate. It is found that carbon-iodine bond scission occurs below ~200 K to deposit iodine and form propyl species from 1-iodopropane and a C3 metallacycle from 1,3-diiodopropane.

Strip-casting technique is used to prepare anisotropic Nd[(Fe,Mo).sub.12][N.sub.x] compounds. It is found that, by this technique, the single-phase Nd[(Fe, Mo).sub.12] compounds could be directly obtained without postannealing at a rolling velocity of 3 m/s and with an Fe-to-Mo ratio of 7.

The roles of chemical composition (X, M and M(sub FW)) of di-transition-metal-substituted gamma-Keggin polytungstates and polymolybdates, [(X(super n+)O4)M2(OH)(sub 2)(M(sub FW))O32](super 8-n)-, on the geometry, electronic structure and magnetic properties of these species are investigated at the density functional level. The results have shown that the change of addenda atom M(sub FW) from W to Mo makes the geometry of Keggin cage slightly smaller and the J-coupling constant, as well as the energy gap deltaE(BS-HS), slightly larger.

The synthesis and spectroscopic and structural characterization of [Tp(super iPr)MoOS(OAr)](sub n) (n = 1, 2; OAr = alkyl substituted phenolate or naphtholate derivative) and the downstream derivatives are reported. The oxosulfide-Mo(VI) complexes serve as precursors to biologically relevant Mo(V) and heterobimetallic MoO(mu-S)Cu species, while also undergo a range of biomimetic reactions.

Density functional theory computations are carried out to study the structure and stability of MoS(sub x) clusters with the change of sulfur coverage at both Mo and S edges. The interaction between Mo and S edges under the variation of sulfur coverage is analyzed with the change of Mo(sub 27)S(sub x) clusters and the stability of triangular MoS(sub x) clusters are discussed.

The electrochemical synthesis of a new family of charge-transfer salts derived from cluster unit [Mo3S7Br6](super 2-) is presented. The electrochemical oxidation of the donor ET molecule in the presence of the triangular anionic cluster [Mo3S7Br6](super 2-) has given rise to a new family of radical salts.

Two Sr2FeMoO6 samples synthesized under different conditions and showing very different magneto transport properties, were analyzed using transmission electron microscopy. The different magneto resistive behaviors observed in the two samples coincide with the formation of different amounts of striped areas intergrown in samples.

Dicarboxylate linked pairs of Mo(sub 2)(super 4+) display a strong dependence of the electronic ground and excited states upon the chemical nature of the linking species. The more intense colors and lower energy absorptions are observed with those compounds having unsaturated dicarboxylate linkers.

Compounds with two quadruply bonded MO(sub 2)(super 4+) units, Mo2(DSAnif)(sub 3) linked by unsaturated dicarboxylate dianions of various lengths is prepared and their spectroscopic and electrochemical properties is studied. The effect of the dimetal units on the cis-trans isomerization of two C = C bonds on the linker is analyzed.

Pulsed electron nuclear double resonance (ENDOR) spectra of nonexchangeable protons in the vicinity of the Mo(V) center of the high pH (hpH) and low pH (lpH) forms of native chicken liver sulfite oxidase (SO) and recombinant human SO are reported. The study suggests the applicability of ENDOR spectroscopy to probe the orientation of the coordinated residue in mutant forms of SO that are catalytically compromised.

The result of low energy electron diffraction (LEED) are measured and showed that an ordered In-PTCDA (perylene-3, 4,9,10-tetracarboxylic dianhydried) system can be formed on MoS2 surface by annealing. The LEED analysis shows that the In-PTCDA species lie titled on the MoS2 surface.

Thin film of SrMoO3 on silica glass substrate by sputtering and the optical and electrical properties of the oxide films are studied. The plasma frequency due to free carriers is obtained by application of a Drude model to reflectivity values, which indicate that the effective mass of the conduction carrier is m(super *)= 2.1m(sub 0).

The possible vibronic behaviors of [Mo][N.sub.2] are described. Additionally an EPR study is presented, which characterizes the electronic configuration and vibronic properties of this complex.

A simple chemical process for synthesizing long, free-standing metal nanowires, where LiMo3Se3 nanowires are used as both reducing agents and sacrificial templates, is reported. These metal nanowires show small ohmic resistances at room temperature, indicating that these wires can be used as interconnects in nanoelectronic circuits.