Download or read book DESORPTION D IONS NEGATIFS STIMULEE PAR IMPACT D ELECTRONS DE BASSE ENERGIE SUR LES MOLECULES CONDENSEES written by MOUSTAPHA.. LACHGAR and published by . This book was released on 2000 with total page 170 pages. Available in PDF, EPUB and Kindle. Book excerpt: CE TRAVAIL DE THESE EST UNE CONTRIBUTION EXPERIMENTAL A L'ETUDE DES INTERACTIONS DES ELECTRONS DE BASSE ENERGIE AVEC LES MOLECULES CONDENSEES SUR UN SUBSTRAT METALLIQUE. LA SONDE DE CES INTERACTIONS EST LA DETECTION DES IONS NEGATIFS QUI DESORBENT. A BASSE ENERGIE, CES IONS SONT FORMES PAR LE MECANISME D'ATTACHEMENT ELECTRONIQUE DISSOCIATIF (AED). L'OBJECTIF DE CE TRAVAIL EST L'ETUDE DES EFFETS DE L'ENVIRONNEMENT SUR LA DESORPTION STIMULEE D'IONS NEGATIFS, ET LA REACTIVITE INDUITE DANS LES FILMS HOMOGENES ET HETEROGENES. POUR CELA, NOUS AVONS ETUDIE LA DESORPTION D'IONS O A PARTIR DE FILMS DE O 2 CONDENSE SUR DIVERS SUBSTRATS MOLECULAIRES PROTIQUES OU NON, AYANT DES MOMENTS DIPOLAIRES VARIABLES (0

Download or read book DYNAMIQUE DE DESORPTION D IONS STIMULEE PAR IMPACT D ELECTRONS DE BASSE ENERGIE 0 25 EV SUR LES MOLECULES O 2 N 2O ET CF 4 CONDENSEES SUR DES SUBSTRATS METALLIQUES written by MOHAMED NEJIB.. HEDHILI and published by . This book was released on 1998 with total page 170 pages. Available in PDF, EPUB and Kindle. Book excerpt: L'INTERACTION D'ELECTRONS DE BASSE ENERGIE (0 - 25 EV) AVEC DES MOLECULES CONDENSEES CONDUIT A LA DESORPTION D'IONS NEGATIFS ET POSITIFS DONT LES SPECTRES DE RENDEMENT ET LES DISTRIBUTIONS D'ENERGIE CINETIQUE PERMETTENT DE DECRIRE LES MECANISMES ET LA DYNAMIQUE DES PROCESSUS EN JEU. DES ETUDES SUR LES MOLECULES O 2, N 2O ET CF 4 CONDENSEES SUR UN METAL (PT) MONTRENT QUE LES MECANISMES (L'ATTACHEMENT DISSOCIATIF ET LA DISSOCIATION DIPOLAIRE) ET LA DYNAMIQUE DE DESORPTION DEPENDENT DES CONDITIONS DE CONDENSATION. - EN MULTICOUCHES DE MOLECULES D'OXYGENE O 2, LA FORMATION DE RESONANCES O - * 2 DE SYMETRIE +, INTERDITES EN PHASE GAZEUSE, CONTRIBUE A LA DESORPTION D'IONS O - ET QUE LA PREDISSOCIATION D'ETATS DE RYDBERG O * 2 EST RESPONSABLE DE LA DESORPTION D'IONS O - ET O + VIA LE PROCESSUS DE DISSOCIATION DIPOLAIRE. - EN MONOCOUCHE OU SUBMONOCOUCHE DE O 2, UN PROCESSUS DE DESORPTION D'IONS O - TRES ENERGETIQUES IMPLIQUANT UN TRANSFERT DE CHARGE DU SUBSTRAT METALLIQUE VERS DES FRAGMENTS NEUTRES O FORMES PAR EXCITATION DISSOCIATIVE PAR IMPACTS D'ELECTRONS SUR O 2 CONDENSE EST MIS EN EVIDENCE. - DES DISTRIBUTIONS D'ENERGIE CINETIQUE D'IONS O - MONTRENT QUE LA DYNAMIQUE DE DESORPTION DEPEND DE L'ENVIRONNEMENT DANS LEQUEL LES MOLECULES O 2 SONT CONDENSEES ET QU'EN PLUS DES COLLISIONS MULTIPLES DES ELECTRONS INCIDENTS ET DES IONS, LES PHENOMENES DE FLUCTUATION DE L'ENERGIE DE POLARISATION ET DE CREATION DE PHONONS DANS LE SUBSTRAT ET LE MILIEU CONDENSE JOUENT UN ROLE IMPORTANT. - ENFIN L'INTERACTION D'ELECTRONS AVEC L'OXYGENE MOLECULAIRE CONDENSE CONDUIT A LA PRODUCTION D'OZONE O 3 EN SURFACE ET EN VOLUME DE L'ADOSORBAT VIA DES REACTIONS ATOMES-MOLECULES, AVEC UN SEUIL A 3.5 EV D'ENERGIE INCIDENTE.

Download or read book Desorption Induced by Electronic Transitions DIET III written by Richard H. Stulen and published by Springer Science & Business Media. This book was released on 2013-03-08 with total page 304 pages. Available in PDF, EPUB and Kindle. Book excerpt: These proceedings are the result of the third international workshop on Desorption Induced by Electronic Transitions, DIET III, which took place on Shelter Island, NY, May. 20-22, 1987. The work contained in this volume is an excellent summary of the current status of the field and should be a valuable reference text for both "seasoned" researchers and newcomers in the field of DIET. Based on the success of the meeting it seems clear that interest and enthusiasm in the field is strong. It is also apparent, from the many lively discussions during the meeting, that many unanswered questions (and controversies) remain to be solved. It was particularly pleasing to see many new participants from new and rapidly advancing fields, ranging from gas phase dynamics to semiconductor processing. The resulting cross-fertilization from these separate but related fields is playing an important role in helping us understand desorption processes at solid surfaces. In general, the topics covered during the course of the workshop over lapped those of both DIET I and DIET II. However, clear advances have been made and in general there is a much more sophisticated understand ing of the physics and chemistry of stimulated desorption. Of particular note in this regard is the gas phase research highlighted in this workshop by the work of Nenner et al. , where new results indicate that in the gas phase, photodissociation can precede or compete strongly with autoion ization and other electronic relaxation pathways.

Download or read book D sorption stimul e d ions n gatifs par impact d lectrons de basse nergie sur des surfaces de diamant hydrog n et oxyg n written by Mohamed Hadj Hamou and published by . This book was released on 2003 with total page 131 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this work, we considered from the experimental point of view, the interaction of low-energy electrons with hydrogenated oxygenated diamond surfaces. We have studied the mechanisms of H ̄and 0 ̄ions desorption from these surfaces, hydrogenated diamond surfaces received particular attention. For this surface, we have proved the existence of Feshbach resonance at 9 eV, which is responsible for H ̄ions desorption, by the direct dissociative electron attachment mechanism at 9 eV, and by indirect dissociative electron attachment at 22 eV. In the other hand dipolar dissociation mechanism contributed to H ̄ions desorption above 14 eV. The two mechanisms are involved probably in the photodesorption of H- ions which we have mentioned in the introductions. Thus, they contribute to the depletion of hydrogen from hydrogenated diamond surfaces and consequently to the degradetion of the negative electronic affinity property. In addition the resonance at 9 eV is responsible for the attenuation of the current of secondary electrons, emmited by the surfaces submitted to electronic bombardment, by the induction of upward energy band bending. The recent studuies in the laboratory showed that this resonance contribute to vibrational excitation of C-H bond. Finally studies as function of incident current intensity and surface temperature showed that if one works with currents lover to 2 nA and temperatures around 500 K, it is possible to avoid the decrease of the secondary electrons emmitted by the surfaces of hydrogenated diamond. Despite the fact that our results are far ahead of industrial use of diamond surfaces, they should be used for optimisation of this surfaces for high technologies applications.

Download or read book Desorption Induced by Electronic Transitions DIET II written by Wilhelm Brenig and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 296 pages. Available in PDF, EPUB and Kindle. Book excerpt: The second workshop on Desorption Induced by Electronic Transitions (DIET II) took place October 15-17, 1984, in SchloB Elmau, Bavaria. DIET II, fol lowing the great success of DIET I (edited by N. H. Tolk, M. M. Traum, J. C. Tully, T. E. Madey and published in Springer Ser. Chem. Phys. , Vol. 24), again brought together over 60 workers in this exciting field. The "hard co re of experts" was essentially the same as in DIET I but the general overlap of participants between the two meetings was small. While DIET I had the function of an exposition of the status of the field DIET II focussed more on new developments. The main emphasis was again on the microscopic under standing of DIET but a number of side aspects and the application of DIET ideas to other fields such as sputtering, laser-induced desorption, fractu re, erosion, etc. were considered, too. New mechanisms and new refined expe rimental techniques were proposed and discussed at the meeting critically but with great enthusiasm. In addition to the talks, there was a continuous poster exhibition which also stimulated extended and excited discussions. This book is a collection of papers summarizing the talks and posters presented at the meeting.

Download or read book DESORPTION D IONS NEGATIFS A PARTIR DE SURFACES BOMBARDEES PAR DES ELECTRONS DE TRES BASSE ENERGIE written by TING-DI.. WU and published by . This book was released on 1992 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: LE MONTAGE OPTIQUE ASSEMBLE ICI EST DESTINE A L'ETUDE DES INTERACTIONS D'ELECTRONS DE BASSE ENERGIE AVEC DES COUCHES ADSORBEES ET LA DESORPTION D'IONS NEGATIFS. IL DIRIGE SUR DES SURFACES PLACEES EN ULTRA-VIDE DES FAISCEAUX ELECTRONIQUES DE DENSITE CONSTANTE ET D'ENERGIE AJUSTABLE ET ASSURE LA COLLECTE ET L'ANALYSE DES IONS NEGATIFS DESORBES. (I) UN PROCESSUS DE DESORPTION RESONNANTE PROVOQUE D'INTENSES DESORPTIONS D'IONS H# SUR LES SURFACES D'ALUMINIUM, DE MAGNESIUM OU DE SILICIUM COUVERTES DE MOLECULES DE VAPEUR D'EAU LORSQUE L'ENERGIE DES ELECTRONS EST VOISINE DE 6,5 EV; CETTE DESORPTION S'ETABLIT DES QUE LE FAISCEAU D'ELECTRONS ARRIVE SUR UNE SURFACE FRAICHEMENT PREPAREE. MAIS, SUR CES SURFACES, LA DESORPTION RESONNANTE D'IONS O# ET OH# N'APPARAIT QU'APRES UNE TRANSFORMATION DES COUCHES ADSORBEES PROVOQUEE PAR UN BOMBARDEMENT ELECTRONIQUE APPLIQUE PLUSIEURS MINUTES. LE MECANISME DE DESORPTION RESONNANTE EST ATTRIBUE A LA DISSOCIATION D'UN ETAT ANTI-LIANT VOISINE DES PROCESSUS ATTACHEMENTS ELECTRONIQUES DISSOCIATIFS OBSERVES EN PHASE GAZEUSE; (II) SUR D'AUTRES METAUX (TI, CR, W, NI) LES DESORPTIONS RESONNANTES A TRES BASSE ENERGIE RESTENT PEU DETECTABLES MEME APRES DES BOMBARDEMENTS ELECTRONIQUES PROLONGES. CES BOMBARDEMENTS PREALABLES SONT SOUVENT INDISPENSABLES POUR PROVOQUER UNE DESORPTION D'IONS O# A PARTIR DE MOLECULES H#2O, CO OU O#2 DANS DES COLLISIONS AU-DELA DE 20 EV. LES CARACTERISTIQUES DE CETTE DESORPTION DEPENDENT FORTEMENT DU SUBSTRAT ET PEU DE L'ADSORBAT; (III) DES ENREGISTREMENTS COMPLEMENTAIRES D'INTENSITE PERMETTENT DE SUIVRE LES TRANSFORMATIONS DES COUCHES ADSORBEES OPEREES PAR LE BOMBARDEMENT ELECTRONIQUE AU TRAVERS DES VARIATIONS DE TRAVAIL DE SORTIE ET DES MODIFICATIONS DE RENDEMENT DE RETRODIFFUSION DES ELECTRONS PAR LA SURFACE

Download or read book DYNAMIQUE DE DESORPTION DES IONS O STIMULEE PAR IMPACT ELECTRONIQUE SUR DES MOLECULES D OXYGENE CONDENSEES SUR UNE SURFACE DE PLATINE written by BRAHIM.. MHARZI and published by . This book was released on 1996 with total page 134 pages. Available in PDF, EPUB and Kindle. Book excerpt: A L'ETAT GAZEUX, LES COMPORTEMENTS ENERGETIQUE ET ANGULAIRE DES IONS FORMES A LA SUITE DE LA FRAGMENTATION D'UN ANION DE COURTE DUREE DE VIE (RESONANCE), APRES ATTACHEMENT ELECTRONIQUE DANS UNE ORBITALE DE LA MOLECULE CIBLE, SONT CORRELES ESSENTIELLEMENT AUX PROPRIETES INTRINSEQUES DU SYSTEME QUANTIQUE E#- - MOLECULE (ENERGIE, SYMETRIE, DUREE DE VIE). LA CONDENSATION DES MOLECULES SUR UNE SURFACE CONDUCTRICE PERTURBE CETTE CORRELATION. LES MESURES DES RENDEMENTS, DES DISTRIBUTIONS D'ENERGIE CINETIQUE ET DES REPARTITIONS ANGULAIRES DES ANIONS QUI DESORBENT DE LA SURFACE METTENT EN EVIDENCE UN CERTAIN NOMBRE DE CHANGEMENTS SUR LES CARACTERISTIQUES DE LA SECTION EFFICACE, DE LA DISTRIBUTION D'ENERGIE CINETIQUE ET DE LA REPARTITION ANGULAIRE D'ANIONS FRAGMENTS PAR RAPPORT A LA PHASE GAZEUSE : LE RENDEMENT DES IONS O#- QUI DESORBENT DE O#2 CONDENSE EN MULTICOUCHE SUR DU PLATINE POLYCRISTALLIN MONTRE DES ETATS DE RESONANCE SUPPLEMENTAIRES NON OBSERVES EN PHASE GAZEUSE ET DES DISTRIBUTIONS D'ENERGIE CINETIQUE RELATIVEMENT LARGES ET DEPLACEES VERS LES BASSES ENERGIES, AINSI QUE DES REPARTITIONS ANGULAIRES PIQUEES SUIVANT LA NORMALE A LA SURFACE ET DECROISSANT RAPIDEMENT LORSQU'ON S'ELOIGNE DE CETTE DIRECTION. L'ENSEMBLE DE CES MODIFICATIONS SEMBLE LIE AUX INTERACTIONS ENTRE LES CONSTITUANTS DE L'ADSORBAT, A LA DISSIPATION DANS LE MILIEU CONDENSE DE L'ENERGIE PRIMAIRE DE L'ELECTRON PENETRANT DANS CE MILIEU AVANT SA CAPTURE PAR UNE MOLECULE ET DES ANIONS TRANSITOIRE ET FRAGMENT FORMES AVANT LA DESORPTION. NOS RESULTATS MONTRENT AUSSI QUE LA PROBABILITE D'EMISSION DE L'ANION FRAGMENT DANS LE VIDE DEPEND DU POTENTIEL DE POLARISATION INDUITE PAR LA CHARGE NEGATIVE LOCALISEE ET DU POTENTIEL IMAGE, DE L'ENERGIE CINETIQUE ET DE L'ANGLE D'EMISSION DE CET ION AVANT SON PASSAGE DANS LE VIDE. D'AUTRES PROCESSUS EVOQUES DANS LA LITTERATURE TELS QUE LE TRANSFERT DE CHARGE ET LA NEUTRALISATION ET LES REACTIONS CHIMIQUES PEUVENT AVOIR LIEU DANS LE MILIEU CONDENSE ET PARTICIPER AUX CARACTERISTIQUES DES ANIONS DETECTES.

Download or read book Desorption Induced by Electronic Transitions DIET V written by Alan R. Burns and published by Springer Science & Business Media. This book was released on 2013-03-07 with total page 344 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume in the Springer Series on Surface Sciences presents a recent account of advances in the ever-broadening field of electron-and photon-stimulated sur face processes. As in previous volumes, these advances are presented as the proceedings of the International Workshop on Desorption Induced by Electronic Transitions; the fifth workshop (DIET V) was held in Taos, New Mexico, April 1-4, 1992. It will be abundantly clear to the reader that "DIET" is not restricted to desorption, but has for several years included photochemistry, non-thermal surface modification, exciton self-trapping, and many other phenomena that are induced by electron or photon bombardment. However, most stimulated surface processes do share a common physics: initial electronic excitation, localization of the excitation, and conversion of electronic energy into nuclear kinetic energy. It is the rich variation of this theme which makes the field so interesting and fruitful. We have divided the book into eleven parts in order to emphasize the wide range of materials that are examined and to highlight recent experimental and theoretical advances. Naturally, there is considerable overlap between sections, and many papers would be appropriate in more than one part. Part I focuses on perhaps the most active area in the field today: electron attachment. Here the detection and characterization of negative ions formed by attachment of elec trons supplied externally from the vacuum are discussed. In addition, the first observations of negative ions formed by substrate photoelectrons are presented.

Download or read book Desorption Induced by Electronic Transitions DIET III written by Richard H. Stulen and published by Springer. This book was released on 1988-06-28 with total page 295 pages. Available in PDF, EPUB and Kindle. Book excerpt: These proceedings are the result of the third international workshop on Desorption Induced by Electronic Transitions, DIET III, which took place on Shelter Island, NY, May. 20-22, 1987. The work contained in this volume is an excellent summary of the current status of the field and should be a valuable reference text for both "seasoned" researchers and newcomers in the field of DIET. Based on the success of the meeting it seems clear that interest and enthusiasm in the field is strong. It is also apparent, from the many lively discussions during the meeting, that many unanswered questions (and controversies) remain to be solved. It was particularly pleasing to see many new participants from new and rapidly advancing fields, ranging from gas phase dynamics to semiconductor processing. The resulting cross-fertilization from these separate but related fields is playing an important role in helping us understand desorption processes at solid surfaces. In general, the topics covered during the course of the workshop over lapped those of both DIET I and DIET II. However, clear advances have been made and in general there is a much more sophisticated understand ing of the physics and chemistry of stimulated desorption. Of particular note in this regard is the gas phase research highlighted in this workshop by the work of Nenner et al. , where new results indicate that in the gas phase, photodissociation can precede or compete strongly with autoion ization and other electronic relaxation pathways.

Download or read book Desorption Induced by Electronic Transitions DIET I written by N. H. Tolk and published by Springer. This book was released on 1983-03-01 with total page 292 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Workshop on Desorption Induced by Electronic Transitions (DIET) took place May 12-14, 1982, in Williamsburg, Virginia. The meeting brought together, for the first time, most of the leading workers in the fields of electron and photon stimulated desorption from surfaces, as well as many workers in related fields, including sputtering, gas-phase photodissociation and solid-state theory. The emphasis of the workshop was on the microscopic mechanism of stimu lated desorption. Many possible mechanisms have been proposed, and a few new ones emerged at the meeting. Though no consensus was reached, many views were espoused and criticized, frequently with considerable enthusiasm. The result was an appraisal of our current understanding of DIET, and a focus on the experimental and theoretical efforts most likely to lead to new insights. This volume is an attempt to record the information exchanged in this very successful workshop and, perhaps, convey some of the excitement of the field of DIET. The book is a collection of papers written by participants in the DIET workshop, including in addition a contribution from Dietrich Menzel, who was unable to attend. Thus, this book represents a complete statement of the state of the art of experimental and theoretical studies of DIET and related phenomena. More importantly, it addresses the interesting unsolved problems, and suggests strategies for unraveling them. We acknowledge the assistance given by the other members of the organizing committee, A. E. de Vries, R. Gomer, M. L. Knotek, D. Menzel and D. P.

Download or read book Desorption Induced by Electronic Transitions written by and published by . This book was released on 1983 with total page 269 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Workshop on Desorption Induced by Electronic Transitions (DIET) took place May 12-14, 1982, in Williamsburg, Virginia. The meeting brought together, for the first time, most of the leading workers in the fields of electron and photon stimulated desorption from surfaces, as well as many workers in related fields, including sputtering, gas-phase photodissociation and solid-state theory. The emphasis of the workshop was on the microscopic mechanism of stimu lated desorption. Many possible mechanisms have been proposed, and a few new ones emerged at the meeting. Though no consensus was reached, many views were espoused and criticized, frequently with considerable enthusiasm. The result was an appraisal of our current understanding of DIET, and a focus on the experimental and theoretical efforts most likely to lead to new insights. This volume is an attempt to record the information exchanged in this very successful workshop and, perhaps, convey some of the excitement of the field of DIET. The book is a collection of papers written by participants in the DIET workshop, including in addition a contribution from Dietrich Menzel, who was unable to attend. Thus, this book represents a complete statement of the state of the art of experimental and theoretical studies of DIET and related phenomena. More importantly, it addresses the interesting unsolved problems, and suggests strategies for unraveling them. We acknowledge the assistance given by the other members of the organizing committee, A. E. de Vries, R. Gomer, M. L. Knotek, D. Menzel and D. P.

Download or read book Energy and Angular Distributions of Ions Induced by Electron Stimulated Desorption from Surfaces written by Claire-Louise Greenwood and published by . This book was released on 1993 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book A Comparative Study of Electron Stimulated Desorption of Positive and Negative Ions from Gases Adsorbed on Metals written by Jeffrey L. Hock and published by . This book was released on 1979 with total page 268 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book PHOTODESORPTION D IONS DANS DES ATOMES ET DES MOLECULES CONDENSES OU ADSORBES written by Laurent Philippe and published by . This book was released on 1994 with total page 214 pages. Available in PDF, EPUB and Kindle. Book excerpt: NOUS PRESENTONS UN TRAVAIL EXPERIMENTAL SUR LA PHOTODESORPTION D'IONS DANS LES ATOMES ET LES MOLECULES CONDENSES OU ADSORBES. NOUS UTILISONS COMME SOURCE DE PHOTONS LE RAYONNEMENT SYNCHROTRON DANS LA GAMME D'ENERGIE 10-150 EV. CE MEMOIRE PRESENTE LA PREMIERE ETUDE DE PHOTODESORPTION D'IONS OU L'ON A PU SIMULTANEMENT SELECTIONNER EN MASSE ET EN ENERGIE CINETIQUE LES IONS DESORBES. NOUS MONTRONS QUE LA DESORPTION D'IONS EST PRINCIPALEMENT INDUITE PAR LA FORMATION D'ETATS ELECTRONIQUES MULTIPLEMENT EXCITES (PAIRES D'EXCITONS, ETATS SATELLITES, DOUBLE ET TRIPLE IONISATION, IONISATION SIMULTANEE DE PLUSIEURS ATOMES). NOS MESURES D'ENERGIES CINETIQUES DES IONS DESORBES MONTRENT QU'EN GENERAL LES ENERGIES CINETIQUES SONT BEAUCOUP FAIBLES QUE CE QUI ETAIT ATTENDU. CECI EST DU AU ROLE DES PROCESSUS DE RELAXATION (EX: FLUORESCENCE) DES ETATS ELECTRONIQUES EXCITES. CEPENDANT DANS LA PLUPART DES CAS LA RELAXATION N'EST PAS COMPLETE ET LA SELECTIVITE DE L'EXCITATION EST PRESERVEE DANS LA DESORPTION (ARGON ET CO CONDENSE EN MULTICOUCHES ET OXYGENE CHIMISORBE SUR LE SILICIUM). POUR LES MOLECULES CONDENSEES EN MULTICOUCHES, NOUS AVONS ETUDIE LES PROCESSUS DE FRAGMENTATION. CES PROCESSUS SE SONT AVERES TRES DIFFERENTS DE LA PHASE GAZEUSE PUISQU'A UNE MEME ENERGIE DE PHOTON SEULS LES ETATS SATELLITES DONNENT DE LA DESORPTION D'IONS FRAGMENTS (CO, CH#4 ET H#2O) ET QUE LES ENERGIES CINETIQUES MESUREES EN DESORPTION D'IONS FRAGMENTS SONT PLUS FAIBLES QUE LES ENERGIES MESUREES EN PHOTOFRAGMENTATION D'IONS. TOUJOURS DANS LES MOLECULES CONDENSEES, NOUS AVONS EXPLIQUE LA FORMATION DES PRODUITS DESORBES COMPLEXES OBSERVES PAR DES REACTIONS ION-MOLECULE EN SURFACE OU PAR LA PHOTOFRAGMENTATION D'AGREGATS EN SURFACE. ENFIN DANS LES ADSORBATS SUR SILICIUM, NOS ETUDES MONTRENT QUE LA PHOTODESORPTION D'IONS PEUT ETRE REALISEE SUR DES SITES PARFAITEMENT BIEN DEFINIS DU POINT DE VUE GEOMETRIQUE ET ELECTRONIQUE

Download or read book ETUDE DES MECANISMES DE DESORPTION IONISATION EN SPECTROMETRIE DE MASSE A TEMPS DE VOL APPLICATION A L ANALYSE DE PESTICIDES written by SOPHIE.. BOURCIER and published by . This book was released on 1996 with total page 307 pages. Available in PDF, EPUB and Kindle. Book excerpt: DANS CE TRAVAIL, NOUS AVONS EU UN DOUBLE OBJECTIF : (I) TESTER LES TECHNIQUES DE DESORPTION-IONISATION COUPLEES A UN TEMPS DE VOL COMME METHODE D'ANALYSE POUR ETUDIER QUELQUES FAMILLES DE PESTICIDES, (II) APPORTER UNE CONTRIBUTION A LA COMPREHENSION DES MECANISMES D'IONISATION PROVOQUES PAR IMPACT D'UN FAISCEAU DE PARTICULES INCIDENTES SUR UN ECHANTILLON SOLIDE. DES SPECTRES DE MASSE DE PESTICIDES ONT ETE REALISES PAR DESORPTION-IONISATION (DI) PAR DES IONS RAPIDES (PD-MS) ET PAR PHOTONS (LD-MS) ET COMPARES POUR EVALUER LA VALEUR INFORMATIVE DE CHAQUE TECHNIQUE. IL S'AVERE, QUE CE SONT LES SPECTRES DE PD-MS QUI PRESENTENT LE PLUS GRAND NOMBRE D'IONS ET PERMETTENT D'IDENTIFIER ET DE DIFFERENCIER LES FAMILLES DE PESTICIDES. UN MELANGE D'IONS MOLECULAIRES QUI SONT, SOIT DES MOLECULES PROTONEES, SOIT DES IONS RADICAUX MOLECULAIRES, EST SOUVENT OBSERVE. AFIN D'OBTENIR DES INFORMATIONS SUR LA QUANTITE D'ENERGIE TRANSMISE AUX ECHANTILLONS DURANT LE PROCESSUS DE DI, NOUS AVONS ETABLI LA FILIATION ENTRE UN ION FRAGMENT ET UN ION MOLECULAIRE PAR COMPARAISON DES SPECTRES DE PD-MS A CEUX OBTENUS PAR LES METHODES QUI ENGENDRENT SELECTIVEMENT MH#+ (IONISATION CHIMIQUE, NH#3, CH#4) ET M#+#. (IMPACT ELECTRONIQUE). NOUS AVONS TRACE, GRACE A LA THERMOCHIMIE, LES DIAGRAMMES D'ENERGIE POTENTIELLE ASSOCIES A CHAQUE FRAGMENTATION OBSERVEE. LES INFORMATIONS OBTENUES NOUS ONT PERMIS D'APPROCHER LES DISTRIBUTIONS EN ENERGIE INTERNE TRANSMISES AU COURS DE LA FORMATION DES IONS PAR PD-MS. L'ENSEMBLE DE NOS RESULTATS PERMET D'AFFIRMER QUE LA PD-MS EST UNE TECHNIQUE PARTICULIEREMENT INTERESSANTE POUR L'ANALYSE DES COMPOSES ETUDIES PUISQU'ELLE APPORTE DE MULTIPLES INFORMATIONS : CELLES OBTENUES HABITUELLEMENT PAR LES TECHNIQUES D'IONISATION CLASSIQUES (IE ET IC) AINSI QUE DE NOUVELLES PROVENANT D'IONS DONT LA FORMATION REQUIERT UNE FORTE ENERGIE.

Download or read book The Fingerprint written by U. S. Department Justice and published by Createspace Independent Publishing Platform. This book was released on 2014-08-02 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The idea of The Fingerprint Sourcebook originated during a meeting in April 2002. Individuals representing the fingerprint, academic, and scientific communities met in Chicago, Illinois, for a day and a half to discuss the state of fingerprint identification with a view toward the challenges raised by Daubert issues. The meeting was a joint project between the International Association for Identification (IAI) and West Virginia University (WVU). One recommendation that came out of that meeting was a suggestion to create a sourcebook for friction ridge examiners, that is, a single source of researched information regarding the subject. This sourcebook would provide educational, training, and research information for the international scientific community.

Download or read book Air Quality Criteria for Lead written by United States. Environmental Protection Agency. Office of Research and Development and published by . This book was released on 1977 with total page 310 pages. Available in PDF, EPUB and Kindle. Book excerpt: