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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.

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Showing 1 to 3 of 3 (0.066 seconds)

Spelling suggestions: "subject:"gasphase cluster"" "subject:"gassphase cluster""

1

Studies of refractory clusters produced from a pulsed arc source

Barran, Perdita Elizabeth January 1998 (has links)
No description available.
541
Gas-phase; Cluster binding energies
2

Estudis teòrics de clusters, superfícies i cristalls d'òxids metàl.lics. Propietats estructurals, electròniques i catalítiques

Calatayud Antonino, Monica 27 June 2001 (has links)
La present tesi doctoral tracta la modelitzacio de diferents estats de la materia: clusters o agregats, superficies i cristalls d'oxids metal.lics. Els metodes disponibles per abordar cada sistema han estat breument descrits, per justificar la seua utilitzacio en diverses aplicacions a materials. Primer, s'han proposat geometries per als agregats de V2O5 cations i neutres en fase gas, i s'han caracteritzat els estats electronics, estructura, espectre de vibracio i enllac quimic. Segon, s'han simulat superficies d'oxids metal.lics i processos d'adsorcio de molecules o atoms metal.lics: CH3OH i O2 sobre SnO2, Cu sobre ZnO. La interaccio adsorbat-superficie te lloc per un mecanisme acid/base, i s'ha caracteritzat la geometria i energia de cada supersistema (mode d'adsorcio, paper dels defectes de superficie). Finalment, s'ha estudiat el cristall de TiO2 en fase anatasa des de multiples punts de vista: descripcio de l'estructura en poliedres, estructura electronica (bandes i densitat d'estats), termodinamic (equacio d'estat) i d'enllac quimic ("Atoms In Molecules"). Les superficies mes estables han estat construides i els efectes de relaxacio avaluats.
adsorcio
O2
CH3OH
ZnO
SnO2
TiO2
V2O5
ELF
DFT
estat solid
gas-phase cluster
catalisi
quimica fisica
538.9
544
546
3

Vanadium Oxide Anions Clusters: Their Abundances, Structures and Reactions with SO₂

Wyrwas, Richard Ben, Jr. 22 November 2004 (has links)
Early transition metal oxide clusters have been a focus of study for several years. The production of vanadium oxide cluster anions in a pulsed helium flow reactor provides a relatively precise way of introducing defect sites and controlling the oxidation state of the vanadium atoms. The composition of the clusters can be changed from the V2O5 stoichiometry, where the vanadium atom is in a +5 oxidation state, to more reduced stoichiometries yielding a mixture of oxidation states containing atoms in the +2 oxidation state. The subsequent addition of reactant gases such as H2O and SO2 yields very intense adsorption reactions as well as a demonstration of the robustness of particular defect free clusters. For example, the cluster has been identified as a defect free cluster where all vanadium atoms are in the +5 oxidation state and all oxygen atoms are predicted to be in the 2- state. The cluster has been shown to not adsorb SO2- while clusters in a reduced oxidation state, such as and readily adsorb one or more SO2 molecules. The adsorption process has been shown to be size dependent, with the smallest monovanadium oxide anions being the most reactive.
Time-of-flight mass spectrometry
Cluster reactivities
Carbon anion clusters
Gas phase cluster reactions
Sulfuric acid production
Vanadium oxide clusters
Metal oxide cluster anions
Vanadium oxide Synthesis Experiments
Surface active agents Experiments
Vanadium oxide Experiments

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