Download or read book PHOTODISSOCIATION DE L OZONE ET DE SES COMPLEXES AVEC DES MOLECULES D HALOGENES X 2 X 2 written by MOHAMMED.. BAHOU and published by . This book was released on 1997 with total page 151 pages. Available in PDF, EPUB and Kindle. Book excerpt: LES REACTIONS PHOTOCHIMIQUES A BASSE TEMPERATURE DANS UN ENVIRONNEMENT SOLIDE SONT ACTUELLEMENT D'UN TRES GRAND INTERET ET LA TECHNIQUE DES MATRICES COUPLEE A LA SPECTROSCOPIE IRTF A PERMIS L'ETUDE : - DE LA PHOTOCHIMIE DE L'OZONE DANS DES SOLIDES PAR IRRADIATION A 266 NM. EN MATRICE D'ARGON, ON OBSERVE ESSENTIELLEMENT LA RECOMBINAISON, DE L'OXYGENE O(#3P) ET DE L'OXYGENE MOLECULAIRE, LA PHOTODISSOCIATION APPARENTE DE L'OZONE N'ETANT DUE QU'A LA MIGRATION HORS DE LA CAGE DE QUELQUES ATOMES D'OXYGENE #1D. EN MATRICE DE N#2, LA PHOTODISSOCIATION DE L'OZONE EST D'ORDRE 1. LES RESULTATS CONFIRMENT QUE, COMME EN GAZ, LA DESEXCITATION DE O(#1D) EN O(#3P)PAR COLLISION AVEC UNE MOLECULE N#2 S'EFFECTUE PAR L'INTERMEDIAIRE EXCITE N#2O QUI SE FRAGMENTE ENSUITE EN N#2 ET O(#3P). - DE LA DIFFUSION DE L'OXYGENE O(#3P) PAR REACTION AVEC LE COMPLEXE N#2O...O#2 FORME PAR PHOTODISSOCIATION DE O#3 EN MATRICE DE N#2. DEUX PROCESSUS DE DIFFUSION ONT ETE MIS EN EVIDENCE. LE PREMIER EST OBSERVE A COURTE DISTANCE ENTRE 14 ET 20 K ET CONDUIT A O#3 PAR REACTION DE L'OXYGENE TRIPLET P ET D'UNE MOLECULE D'OXYGENE EN POSITION DE PLUS PROCHE VOISIN. LE SECOND A LIEU A PARTIR DE 20 K ET CONDUIT A N#2O ET O#3. - DE LA PHOTODISSOCIATION DE #1#8O#3 (888) DANS UNE MATRICE D'OXYGENE PAR IRRADIATION A 693 NM. L'OZONE EST TRANSFORME EN ESPECES 668 ET 686 QUI SONT ENSUITE TRANSFORMEES EN #1#6O#3 PAR ECHANGE ENTRE LES ATOMES #1#8O OU #1#6O. LA PHOTODISSOCIATION DE L'ESPECE 888 SUIT UNE LOI CINETIQUE DU PREMIER ORDRE. LA RECOMBINAISON DE L'OXYGENE 8 AVEC L'OXYGENE NATUREL CONDUIT MAJORITAIREMENT A L'ESPECE 668 ET NON A L'ESPECE SYMETRIQUE 686. - DES COMPLEXES DE L'OZONE AVEC CL#2, BR#2 ET BRCL EN MATRICE D'ARGON. LES TROIS MODES FONDAMENTAUX DE LA MOLECULE D'OZONE COMPLEXEE ONT ETE IDENTIFIES. LES COMPLEXES SONT DISSYMETRIQUES, L'INTERACTION DES HALOGENES SE FAISANT AVEC UN OXYGENE TERMINAL DE L'OZONE. DANS LE CAS DE BRCL, UN SEUL COMPLEXE DANS LEQUEL LE BROME EST LIE A L'OZONE EST OBSERVE. LES CALCULS AB INITIO ONT ABOUTI A L'OPTIMISATION D'UNE STRUCTURE POUR CHAQUE COMPLEXE, EN BON ACCORD AVEC LES OBSERVATIONS EXPERIMENTALES. LA PHOTODISSOCIATION DES COMPLEXES O#3:BR#2 ET O#3:BRCL A LIEU DANS LE VISIBLE, A DES LONGUEURS D'ONDE OU L'OZONE MONOMERE N'EST PAS DISSOCIE. POUR LA PREMIERE FOIS L'ISOMERISATION A 870 NM DE BRBRO ET DE BRCLO EN BROBR ET BROCL RESPECTIVEMENT ET L'ISOMERISATION A 633 NM DE CLBRO A BRCLO EST OBSERVEE.

Download or read book Infrared Spectroscopy of Symmetric and Spherical Top Molecules for Space Observation Volume 2 written by Pierre-Richard Dahoo and published by John Wiley & Sons. This book was released on 2021-10-26 with total page 322 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book, Volume 4 in the series, is dedicated to the relationship between laboratory spectroscopy, recording ever-more-complex spectra using increasingly powerful instruments benefiting from the latest technology, and the development of observation using instruments that are embedded in mobile probes or nanosatellites. The theoretical models described in Volumes 1, 2 and 3 are used in this volume, applying the cumulant theorem in the mean-field theory framework to interpret the near and mid-infrared spectra of symmetric top molecules, such as ammonia (NH3) and spherical molecules, such as methane (CH4). These molecules can be isolated in their gaseous form or subjected to the environmental constraints of a nano-cage (a substitution site, clathrate, fullerene or zeolite) or surfaces. These methods are not only valuable in the fields of environmental sciences, planetology and astrophysics, but also fit into the framework of data processing and the concept of Big Data.

Download or read book ETUDE EN MATRICE DE LA PHOTODISSOCIATION DU NITRATE DE CHLORE MOLECULE RESERVOIR STRATOSPHERIQUE IDENTIFICATION DES COMPLEXES ENTRE C10NO2 C1NO NO ET HC1 OU HBR written by ARMELLE DE.. SAXCE and published by . This book was released on 1994 with total page 259 pages. Available in PDF, EPUB and Kindle. Book excerpt: AFIN D'APPORTER DES INFORMATIONS CONCERNANT LES PROCESSUS ELEMENTAIRES DES REACTIONS HETEROGENES STRATOPHERIQUES, NOUS AVONS UTILISE LA TECHNIQUE DES MATRICES COUPLEE A LA SPECTROSCOPIE IRTF POUR ETUDIER I) LA PHOTODISSOCIATION DU NITRATE DE CHLORE, MOLECULE RESERVOIR STRATOSPHERIQUE II) LES COMPLEXES POUVANT SE FORMER ENTRE C1ONO#2, C1NO, NO ET HC1 OU HBR. LA PHOTODISSOCIATION DU NITRATE DE CHLORE A LIEU SOUS 300 NM SELON DEUX PROCESSUS I) C1ONO#2C1ONO+O(#3P) II) C1ONO#2C1+NO+O#2 ET DES ETUDES CINETIQUES SUGGERENT QUE CES DEUX REACTIONS POURRAIENT AVOIR POUR ORIGINE UNE ESPECE EXCITEE COMMUNE. NOS EXPERIENCES ONT PERMIS DE METTRE EN EVIDENCE UNE INTERACTION TRES FAIBLE ENTRE LE GROUPEMENT NO' DE C1O'NO#2 ET HC1. TROIS CONFORMATIONS DU COMPLEXE C1NO:HC1 SONT OBSERVEES EN MATRICE D'ARGON ET LEURS DEPLACEMENTS RELATIFS, DE L'ORDRE DE 5.10#-#2, CARACTERISENT UNE LIAISON HYDROGENE FAIBLE ENTRE LES DEUX SOUS MOLECULES C1NO ET HC1. LA PHOTODISSOCIATION UV DE CE COMPLEXE N'EST PAS OBSERVEE DANS NOS CONDITIONS EXPERIMENTALES. UNE FAIBLE LIAISON HYDROGENE A ETE MISE EN EVIDENCE ENTRE NO OU (NO)#2 ET HX (X=C1,BR). POUR LE COMPLEXE NO:HC1, DES CALCULS AB INITIO (CASSCF) SUGGERENT LA STRUCTURE LINEAIRE C1HNO. LA PHOTODISSOCIATION DE NO:HX ET (NO)#2:HX A LIEU SOUS 300 NM ET CONDUIT RESPECTIVEMENT A XNO ET A XNO:HNO QUI EST A SON TOUR DISSOCIE POUR DONNER XNO. LES OBSERVATIONS CONCERNANT L'OZONE FORME EN MATRICE D'OXYGENE LORS DE LA PHOTODISSOCIATION DU NITRATE DE CHLORE ONT CONDUIT A UNE ETUDE PERMETTANT L'IDENTIFICATION D'UN COMPLEXE ENTRE L'OZONE ET L'OXYGENE ATOMIQUE DANS SON ETAT FONDAMENTAL

Download or read book Photodissociation of H 2 S D 2 S Molecules written by and published by . This book was released on 1989 with total page 105 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Excited States in Quantum Chemistry written by Cleanthes A. Nicolaides and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 572 pages. Available in PDF, EPUB and Kindle. Book excerpt: It is undoubtedly true that much of the progress in the quant~m theory of matter is due to the remarkable success of the independent particle model (IPM)--especially in describing ground states. However, the accurate experimental results of the last 10 years or so, on a variety of spectroscopic phenomena and chemical processes which involve the Excited State, and the related failure of the IPM to reproduce accurately--in many cases, even qualitatively--the observed data, have sent to theorists a clear message: There is need to create and/or apply general and useful approaches to the many-electron problem of the excited state which go beyond the IPM, treat electron correlation and relativity and explain or predict all relevant physical or chemical information with consistent accuracy. This book contains articles devoted mainly to some of the most important new developments in Quantum Chemistry concerning the theoretical foundations and the computational implementation of many-body approaches to the quantitative and detailed under standing of the electronic excited states of atoms, molecules and solids. Furthermore, it contains experimental and pheno menological articles on Photoelectron and Auger spectroscopy, Lifetime measurements and Organic Photochemistry. In combination or individually, these articles constitute a good description of some current theoretical and experimental work on the electronic structure and spectroscopy of atoms, molecules, polymers, surfaces, metal oxides and amorphous solids.

Download or read book The Nonclassical Ion Problem written by Herbert C. Brown and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 312 pages. Available in PDF, EPUB and Kindle. Book excerpt: 1. That Fascinating Nonclassical Ion Problem.- 1.1. Introduction.- 1.2. Origins.- 1.3. The Nonclassical Ion Era.- 1.4. Steric Assistance.- 1.5. An Alternative Interpretation.- 1.6. The Rococo Period of Carbonium Ion Structures.- 1.7. Difficulties in Challenging an Accepted Theory.- 1.8. Further Difficulties-A "Soft" Theory.- 1.9. Still Further Difficulties-Selective Reviews.- 1.10. Conclusion.- Comments.- 2. Steric Assistance in Solvolytic Processes.- 2.1. Introduction.- 2.2. Steric Assistance in the Solvolysis of Highly Branched Alkyl Derivatives.- 2.3. Steric Assistance in the Relative Effec.

Download or read book Elements of Organic Photochemistry written by D. Cowan and published by Springer. This book was released on 2012-04-25 with total page 586 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the past fifteen years organic photochemistry has undergone a greater change and has stimulated more interest than probably any other area of organic chemistry. What has resulted is a population explosion, that is, an ever-increasing number of organic chemists are publishing important and exciting research papers in this area. Professor Bryce-Smith in the introduc tion to a recent volume of the Specialist Periodical Report (Photochemistry, Volume 6), which reviews the photochemical literature in yearly intervals, states that "the flood of photochemical literature is showing some signs of abatement from the high levels of two or three years ago .... " However, Volume 6 of that periodical contains 764 pages of excellent but very concise reviews. We expect the development of the mechanistic aspects of organic photo chemistry to continue at the present pace as new methods are developed to probe in increasing detail and shorter time scales the photochemical dynamics of both old and new photoreactions. Since photochemistry is no longer the sole domain of the specialist, it is relatively safe to predict a dramatic increase in the near future of the synthetic and industrial uses of organic photo chemistry .