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Excitation, electrons

Heterogeneous photochemical reactions fall in the general category of photochemistry—often specific adsorbate excited states are involved (see, e.g.. Ref. 318.) Photodissociation processes may lead to reactive radical or other species electronic excited states may be produced that have their own chemistry so that there is specificity of reaction. The term photocatalysis has been used but can be stigmatized as an oxymoron light cannot be a catalyst—it is not recovered unchanged. [Pg.738]

A DIET process involves tliree steps (1) an initial electronic excitation, (2) an electronic rearrangement to fonn a repulsive state and (3) emission of a particle from the surface. The first step can be a direct excitation to an antibondmg state, but more frequently it is simply the removal of a bound electron. In the second step, the surface electronic structure rearranges itself to fonn a repulsive state. This rearrangement could be, for example, the decay of a valence band electron to fill a hole created in step (1). The repulsive state must have a sufficiently long lifetime that the products can desorb from the surface before the state decays. Finally, during the emission step, the particle can interact with the surface in ways that perturb its trajectory. [Pg.312]

These results do not agree with experimental results. At room temperature, while the translational motion of diatomic molecules may be treated classically, the rotation and vibration have quantum attributes. In addition, quantum mechanically one should also consider the electronic degrees of freedom. However, typical electronic excitation energies are very large compared to k T (they are of the order of a few electronvolts, and 1 eV corresponds to 10 000 K). Such internal degrees of freedom are considered frozen, and an electronic cloud in a diatomic molecule is assumed to be in its ground state f with degeneracy g. The two nuclei A and... [Pg.405]

Classic examples are the spontaneous emission of light or spontaneous radioactive decay. In chemistry, an important class of monomolecular reactions is the predissociation of metastable (excited) species. An example is the fonnation of oxygen atoms in the upper atmosphere by predissociation of electronically excited O2 molecules [12, 13 and 14] ... [Pg.765]

Lee M, Flaseltine J N, Smith A B III and Flochstrasser R M 1989 Isomerization processes of electronically excited stiibene and diphenylbutadiene in liquids Are they one-dimensional J. Am. Chem. See. Ill 5044-51... [Pg.867]

Detailed analyses of the above experiments suggest that the apparent steps in k E) may not arise from quantized transition state energy levels [110.111]. Transition state models used to interpret the ketene and acetaldehyde dissociation experiments are not consistent with the results of high-level ab initio calculations [110.111]. The steps observed for NO2 dissociation may originate from the opening of electronically excited dissociation chaimels [107.108]. It is also of interest that RRKM-like steps in k E) are not found from detailed quantum dynamical calculations of unimolecular dissociation [91.101.102.112]. More studies are needed of unimolecular reactions near tln-eshold to detennine whether tiiere are actual quantized transition states and steps in k E) and, if not, what is the origin of the apparent steps in the above measurements of k E). [Pg.1035]

Such electronic excitation processes can be made very fast with sufficiently intense laser fields. For example, if one considers monochromatic excitation with a wavenumber in the UV region (60 000 cm ) and a coupling strength / he 4000 (e.g. 1 Debye in equation (A3.13.59), / 50 TW cm ),... [Pg.1062]

Another example of a teclmique for detecting absorption of laser radiation in gaseous samples is to use multiphoton ionization with mtense pulses of light. Once a molecule has been electronically excited, the excited state may absorb one or more additional photons until it is ionized. The electrons can be measured as a current generated across the cell, or can be counted individually by an electron multiplier this can be a very sensitive technique for detecting a small number of molecules excited. [Pg.1123]

Liebsch A 1997 Electronic Excitations at Metal Surfaces (New York Plenum)... [Pg.1302]

So far we have exclusively discussed time-resolved absorption spectroscopy with visible femtosecond pulses. It has become recently feasible to perfomi time-resolved spectroscopy with femtosecond IR pulses. Flochstrasser and co-workers [M, 150. 151. 152. 153. 154. 155. 156 and 157] have worked out methods to employ IR pulses to monitor chemical reactions following electronic excitation by visible pump pulses these methods were applied in work on the light-initiated charge-transfer reactions that occur in the photosynthetic reaction centre [156. 157] and on the excited-state isomerization of tlie retinal pigment in bacteriorhodopsin [155]. Walker and co-workers [158] have recently used femtosecond IR spectroscopy to study vibrational dynamics associated with intramolecular charge transfer these studies are complementary to those perfomied by Barbara and co-workers [159. 160], in which ground-state RISRS wavepackets were monitored using a dynamic-absorption technique with visible pulses. [Pg.1982]

In the ideal case for REMPI, the efficiency of ion production is proportional to the line strength factors for 2-photon excitation [M], since the ionization step can be taken to have a wavelength- and state-mdependent efficiency. In actual practice, fragment ions can be produced upon absorption of a fouitli photon, or the ionization efficiency can be reduced tinough predissociation of the electronically excited state. It is advisable to employ experimentally measured ionization efficiency line strengdi factors to calibrate the detection sensitivity. With sufficient knowledge of the excited molecular electronic states, it is possible to understand the state dependence of these intensity factors [65]. [Pg.2083]

For two Bom-Oppenlieimer surfaces (the ground state and a single electronic excited state), the total photodissociation cross section for the system to absorb a photon of energy ai, given that it is initially at a state x) with energy can be shown, by simple application of second-order perturbation theory, to be [89]... [Pg.2304]

In a defect-free, undoped, semiconductor, tliere are no energy states witliin tire gap. At 7"= 0 K, all of tire VB states are occupied by electrons and all of the CB states are empty, resulting in zero conductivity. The tliennal excitation of electrons across tire gap becomes possible at T > 0 and a net electron concentration in tire CB is established. The electrons excited into tire CB leave empty states in tire VB. These holes behave like positively charged electrons. Botli tire electrons in the CB and holes in tire VB participate in tire electrical conductivity. [Pg.2881]

Sensitivity levels more typical of kinetic studies are of the order of lO molecules cm . A schematic diagram of an apparatus for kinetic LIF measurements is shown in figure C3.I.8. A limitation of this approach is that only relative concentrations are easily measured, in contrast to absorjDtion measurements, which yield absolute concentrations. Another important limitation is that not all molecules have measurable fluorescence, as radiationless transitions can be the dominant decay route for electronic excitation in polyatomic molecules. However, the latter situation can also be an advantage in complex molecules, such as proteins, where a lack of background fluorescence allow s the selective introduction of fluorescent chromophores as probes for kinetic studies. (Tryptophan is the only strongly fluorescent amino acid naturally present in proteins, for instance.)... [Pg.2958]

Ireland J F and Wyatt PAH 1976 Acid-base properties of electronically excited states of organic molecules Adi/. Rhys. Org. Chem. 12 131-221... [Pg.2969]

Agranovioh V M and Galanin M D 1982 Electronic Excitation Energy Transfer in Condensed Maffer (Amsterdam Elsevier/North-Flolland)... [Pg.3030]

Barzykin A V, Barzykina N S and Fox M A 1992 Electronic excitation transport and trapping in micellar systems— Monte-Carlo simulations and density expansion approximation Chem. Rhys. 163 1-12... [Pg.3031]


See other pages where Excitation, electrons is mentioned: [Pg.310]    [Pg.310]    [Pg.306]    [Pg.432]    [Pg.810]    [Pg.873]    [Pg.1006]    [Pg.1062]    [Pg.1103]    [Pg.1161]    [Pg.1249]    [Pg.1307]    [Pg.1314]    [Pg.1319]    [Pg.1785]    [Pg.2060]    [Pg.2066]    [Pg.2082]    [Pg.2139]    [Pg.2173]    [Pg.2187]    [Pg.2227]    [Pg.2322]    [Pg.2486]    [Pg.2492]    [Pg.2946]    [Pg.2963]    [Pg.2986]    [Pg.2998]    [Pg.3017]    [Pg.3017]    [Pg.3018]    [Pg.3026]    [Pg.3032]   
See also in sourсe #XX -- [ Pg.565 , Pg.566 ]

See also in sourсe #XX -- [ Pg.565 , Pg.566 ]

See also in sourсe #XX -- [ Pg.128 , Pg.129 ]

See also in sourсe #XX -- [ Pg.565 , Pg.566 ]

See also in sourсe #XX -- [ Pg.524 , Pg.526 ]

See also in sourсe #XX -- [ Pg.582 , Pg.583 ]

See also in sourсe #XX -- [ Pg.553 , Pg.554 ]




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Adsorbed species electron excitation

Alkaline earth metal atoms electronically excited

Alkene electronically excited states

Anharmonicity excited electronic states

Autoionization electron impact excitation

Avogadro’s number Forster electronic excitation energy transfer

Axial trapping, molecular dyes in zeolite channels, Forster electronic excitation

Basis sets vertical electronic excitation

Bimolecular Reactions of Electronically Excited Species

Bulk electronic excitations

C2H2 excited electronic state

Carbon electronic excitation energy

Carbon electronically excited

Carbonyl group excited electronic states

Chemiluminescence electronic excitation yields

Coincidence experiments electron impact excitation

Configuration interaction excited electronic states

Conjugated oligothiophenes, electronic excited

Conjugated oligothiophenes, electronic excited states

Control systems electronic excitation

Core electron excitation

Core electron excitation binding energies

Core electron excitation energy level diagram

Core electron excitation relaxation studies

Core electron excitation selective

Core electrons excitation energy

Coupled dynamics in electronic excitation

Coupling mechanism electronic excitations

Crystals, electron excitation migration

Cylinder morphology, molecular dyes in zeolite Forster electronic excitation energy transfer

Deformation density electronic excited state

Density functionals electronic excitation energy

Diacetylenes electronically excited

Dispersive electronic excitation transport

Dissociative electron attachment excitation

Doubly excited electron configuration

Doubly excited electron configuration calculation

Dye molecules, zeolite L channels electronic excitation energy transfer

Effect of electronic excitation in reactant ions

Electron Excitation Studies of Anodic Dissolution Mechanisms

Electron Excitation at Surfaces

Electron Transfer Processes between Excited Molecules and Semiconductor Electrodes

Electron Transfer Reaction of the Excited State

Electron beam excitation

Electron bombardment, giving excited

Electron correlation excitation probabilities

Electron correlation methods excited Slater determinants

Electron correlation methods excited states

Electron density distribution excited state

Electron distribution excited state

Electron exchange excitation transfer

Electron excitation channels, decay

Electron excitation current density

Electron excitation probability

Electron excitation probability approximation

Electron excitation probability atomic orbitals approximation

Electron excitation probability states

Electron excitation spectra

Electron excitation spectra of diatomic molecules

Electron excitation, construction algorithms

Electron excitation, in solids

Electron excitation, surface analysis

Electron excitation, transfer

Electron excited Auger spectra

Electron excited state

Electron impact excitation of ions from

Electron impact excitation of ions from organics

Electron in excited state

Electron paramagnetic resonance excited states

Electron photo-excitation

Electron transfer excited organic species

Electron transfer from MLCT excited states

Electron transfer from redox sites of proteins to excited simple molecules

Electron transfer in the excited state

Electron transfer process excitation

Electron tunneling in reactions of excited organic molecules

Electron valence excitation

Electron-Hole Pair Excitation

Electron-atom scattering excitation

Electron-excitation states

Electron-excitation states optically forbidden

Electron-excitation states triplet

Electron-excited state of atoms and molecules

Electron-hole excitation

Electron-impact rovibrational excitation of molecules

Electron-impact spectroscopy excitation

Electron-induced excitation

Electron-transfer mechanism, excited state

Electron-vibrational excited states in molecular crystals

Electronic Excitation Biomolecular Transfer

Electronic Excitation Energies and Transition Moments

Electronic Excitation and Ionization Energies

Electronic Excitation and Photophysical Processes

Electronic Excitation in Molecules

Electronic Excitations and Energy Transfer in PCSs

Electronic Excitations in Conjugated Polymers

Electronic Excitations in Oligothiophenes

Electronic Excited States of Conjugated Oligothiophenes

Electronic Transitions and Lifetime of Excited States in Porphyrin-Based Compounds

Electronic absorption spectra excitation, collisional

Electronic absorption spectroscopy bonding, excited-state spectroscopic

Electronic characterization techniques valence excitation spectroscopy

Electronic charge excitations

Electronic configuration excited state

Electronic elementary excitation

Electronic exchanges excited-state

Electronic excitation

Electronic excitation Franck-Condon principle

Electronic excitation Jablonski diagram

Electronic excitation between complementary orbitals

Electronic excitation between singlet states

Electronic excitation cross section

Electronic excitation energy

Electronic excitation energy 588 INDEX

Electronic excitation energy Stokes shift

Electronic excitation energy differences

Electronic excitation energy excited triplet state

Electronic excitation energy fluorescence

Electronic excitation energy phosphorescence

Electronic excitation energy relaxation

Electronic excitation energy selection rules

Electronic excitation energy transfer

Electronic excitation fluorescence

Electronic excitation frequencies

Electronic excitation in atomic species

Electronic excitation in molecular

Electronic excitation internal conversion

Electronic excitation intersystem crossing

Electronic excitation phosphorescence

Electronic excitation photochemical reactions

Electronic excitation probability

Electronic excitation quantum chemical calculations

Electronic excitation quantum yields

Electronic excitation quantum yields chemiluminescence

Electronic excitation section Scattering

Electronic excitation spectrum

Electronic excitation transfer

Electronic excitation transfer between inert gas atoms

Electronic excitation transport

Electronic excitation, defect creation

Electronic excitation, local control theory

Electronic excitation, propagation

Electronic excitations and surface chemistry

Electronic excitations conjugation effects

Electronic excitations singlet states

Electronic excitations triplet states

Electronic excitations, experimental investigation

Electronic excited

Electronic excited

Electronic excited molecular packing

Electronic excited polythiophenes

Electronic excited singlet states

Electronic excited state proton transfer:

Electronic excited states

Electronic excited states Hamiltonian

Electronic excited states Time-dependent

Electronic excited states basis functions

Electronic excited states initial guess

Electronic excited states molecular structure

Electronic excited states path integral

Electronic excited states semiempirical

Electronic excited states spectrum intensities

Electronic excited states state averaging

Electronic excited states theoretical approach

Electronic geometric phase factors excitation

Electronic ground and excited states

Electronic relaxation of excited molecules

Electronic spin multiplicity Excited-state interactions with

Electronic state, excited, numerical model

Electronic states and excitations

Electronic structure excitations

Electronic structure excited state configurations

Electronic structure methods for excited states

Electronic system excitation process

Electronical excitation

Electronical excitation

Electronically Excited Halogen Atoms (Husain and Donovan)

Electronically Excited Halogen Atoms (Hussain and Donovan)

Electronically Excited reactants

Electronically excited atoms

Electronically excited halogen atoms

Electronically excited halogen atoms atomic transitions

Electronically excited isomers

Electronically excited levels

Electronically excited molecule

Electronically excited molecule energy level diagrams

Electronically excited molecule possible fates

Electronically excited molecule primary processes

Electronically excited molecules geometry

Electronically excited molecules photophysical processes

Electronically excited molecules physical properties

Electronically excited molecules potential energy diagram

Electronically excited molecules rotational

Electronically excited molecules, structure

Electronically excited oxygen atoms

Electronically excited quinones

Electronically excited species

Electronically excited species, deactivation

Electronically excited state reaction paths

Electronically excited states

Electronically excited states Hartree-Fock theory

Electronically excited states of organic molecules, acid-base properties

Electronically excited states, formation

Electrons excitation energy

Electrons excitation studies

Electrons ground and excited states

Electrons lowest excitation state

Electrons optical excitations

Electrons super excited

Electrons, excitation by photons

Electrons, excited

Electrons, excited

Energetics electronic excitations

Energy Efficiency of Plasma-Chemical Processes Stimulated by Electronic Excitation and Dissociative Attachment

Energy Exchange with Electronically Excited Molecules

Energy deposition process electronic excitation

Energy excited electronic

Energy selectivity electronic excitation

Energy transfer in electronically excited

Ethylene, electron impact excitation

Excitation by electron impact

Excitation conduction electrons

Excitation electron-impact

Excitation energy electronic partition

Excitation energy, ionization potential, and electron affinity (RHF approach)

Excitation of Core Electrons

Excitation of Valence Electrons

Excitation of electrons

Excitation temperatures, electronic

Excitation transfer collisions electronic

Excitation, electronic classifications

Excitation, electronic excited states involved

Excitation, electronic exciton states

Excitation, electronic experimental evidence, sources

Excitation, electronic fluorescence sensitization

Excitation, electronic hopping model

Excitation, electronic interaction mechanisms involved

Excitation, electronic materials

Excitation, electronic multistep transfer

Excitation, electronic pigments

Excitation, electronic single-step transfer

Excitation, electronic singlet-higher triplet transfer

Excitation, electronic strong coupling, absorption spectra

Excitations of single electrons

Excited Electronic States in Isolated

Excited Electronic transitions)

Excited State Electron and Energy Transfer Reactions

Excited State Electronic Crossovers

Excited State Electronic Structure Theory

Excited electron correlation methods

Excited electron-donor molecule

Excited electronic configuration

Excited electronic states coupled-cluster

Excited electronic states, hydrogen transfer

Excited electronic states, hydrogen transfer tautomerization

Excited electronic states, ultrafast cluster

Excited electronic tunneling barrier

Excited interfacial electron transfer

Excited ions excitation, electronic

Excited molecular, structure electronically

Excited molecular, structure of electronically

Excited molecules, structure of electronically

Excited species electron configurations

Excited state decay electron transfer

Excited state electron configuration

Excited state electron transfer

Excited state electron transfer process

Excited state level, electronic quenching

Excited state of electrons

Excited state of the electron

Excited state outer sphere electron transfer reactions

Excited states electronic structure

Excited states multi-electron processes

Excited states of f electron systems

Excited-State Electron Exchange

Excited-state dynamics, time-resolved electronic relaxation

Excited-state electron-transfer reactions

Excited-state populations electronic excitation

Excited-state proton-electron simultaneous transfer

Fate of Electron Excitation Inside Membranes

Flame electronically excited atoms

Fluorescence detection electron excitation

Formation of electronically excited states

Fragmentation electron impact excitation

Front trapping, molecular dyes in zeolite channels, Forster electronic excitation

Front-back trapping, molecular dyes in zeolite channels, Forster electronic excitation

General Equation for the Removal of Electronically Excited Halogen Atoms

Half-electron excited singlet states

Heterogeneous de-excitation of electronically excited particles

Hydrogen transfer tautomerization, excited electronic

INDEX excited electronic states

Incoherent electronic excitation

Incoherent electronic excitation transport

Inner-shell electron excitation spectroscopy

Interfacial electron transfer molecular excitations

Internal conversion, of electronically excited

Internal electron excitation

Intramolecular charge transfer electronic excitation

Lifetime electronically excited states

Lifetimes of excited electronic states

Light Absorption and Electronically-excited States

Light electron excitation

Light excited electrons

Lowest excited electronic state

Luminescence excited electrons

MO Models of Electronic Excitation

MO model, electronic excitation light absorption

Markoff chain, molecular dyes in zeolite channels, Forster electronic excitation

Mercury atom, electronic excitation

Metal halides, reactions yielding electronically excited

Metal oxides reactions yielding electronically excited

Migration of electron excitation

Molecular beam magnetic resonance of electronically excited molecules

Molecular chemistry electron impact excitation

Molecular distortions in excited electronic

Molecular distortions in excited electronic damping factor effect

Molecular distortions in excited electronic displacement effect

Molecular distortions in excited electronic states

Molecular vibration electronic excitation

NH in Electronically Excited States of the Singlet and Triplet Manifold

Na effect of electronic excitation

Nitric electronically excited, from

Nitrogen dioxide, electronically excited, from

Nitrogen electronically excited, from

Non-Linear Excitations and the Electronic Structure of Conjugated Polymers

Nuclear excitation by electron transition

Nuclear relaxation, core electron excitation

Numerical computations excited electronic state

Oligothiophenes electronic excitations

One-electron excitation

Photo-excitation free electron

Photo-excited electrons

Photochemical reactions involving electronically excited oxygen

Photodissociation electronic state excitation

Photoluminescence electronic excitation energy

Photophysical deactivation of electronic excited states

Physical chemistry excited electronic state

Point trapping, molecular dyes in zeolite channels, Forster electronic excitation

Polarizable continuum model excited electronic states

Polymer molecule, electronic states excitation

Population of electronically excited states

Potential energy curves electronic excitation

Potential energy curves in excited electronic states

Production of Excited Molecules by Electron Transfer

Proton Transfer in Electronically Excited Molecules (Klopffer)

Proton Transfers in the Electronic Excited State

Proton transfer from excited electronic

Proton transfer from excited electronic states

Quantum Chemical Calculations of Electronic Excitation

Quencher of electronically excited state

Quenching of Electronically Excited NF

R.C. Kamatak, Electronic excitation in atomic species

Radiationless transfer of electronic excitation

Reaction with electronically excited

Reaction with electronically excited singlet states

Reactions of Electronically Excited Halogen Atoms

Reactions of Electronically Excited Noble Gas Atoms

Reactions of Electronically Excited States

Reactions of electronically excited alkaline earth atoms

Reactions of electronically excited ions

Reciprocal rates, electronically excited

Reciprocal rates, electronically excited states

Recombination reactions electronic excitation

Redox properties excited electronic states

Relationship between Electron and Electronic Excitation Transfer

Relativistic Pseudopotential Calculations for Electronic Excited States

Relaxation of Electronically Excited Atoms and Molecules

Relaxation of electronic excited state

Second-order vibrational perturbation theory excited electronic states

Semiconductors electronic excitation

Sensitizers electronically excited, oxidation

Shock-induced Electronic Excitations

Simple quantum chemical models of electronic excitation

Simultaneous pair electronic excitations

Single electron excitations

Single/double excitation configurational electron correlation

Slow electrons rotational excitation

Slow electrons triplet state excitation

Slow electrons vibrational excitation

State preparation electronic excitation

Structure of electronically excited

Supramolecularly organized luminescent dye electronic excitation energy transfer

Surface scattering electron-hole pair excitation

Temperature electronic excitation onset

The Nature of Electronic Excitations

The Nature of Electronic Excitations in Matter (Polymer Blends)

The Nature of Electronically Excited States

The Quantum-Classical Density Operator for Electronically Excited Molecular Systems

Thermal excitation of electrons

Thermodynamic Aspects of Excited State Electron Transfer Reactions

Time scales electronic excitation

Time-dependent density functional theory electronic excitations

Time-resolved spectroscopy electronically excited states

Trap fluorescence, molecular dyes in zeolite channels, Forster electronic excitation

Tunneling in Electron Transfer Reactions of Excited Molecules

Two-dimensional electronic excitation

Two-electron excitations

Two-electron excited states

Ultrafast electronic-excitation energy

Ultrafast electronic-excitation energy transfer

Ultrafast relaxation electronically excited states

Ultraviolet electron line excitation

Ultraviolet spectroscopy electronic excitations

Vibrationally mediated photodissociation of molecules via excited electronic states

Water electronic excitation

Wave function, electronic excited state

X-ray excited auger electron

X-ray excited auger electron spectroscopy

Zeolite L channels, supramolecularly organized electronic excitation energy transfer

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