Big Chemical Encyclopedia

Chemical substances, components, reactions, process design ...

Articles Figures Tables About

Electron excitation probability states

The one exception to this is the INDO/S method, which is also called ZINDO. This method was designed to describe electronic transitions, particularly those involving transition metal atoms. ZINDO is used to describe electronic excited-state energies and often transition probabilities as well. [Pg.220]

In photoluminescence one measures physical and chemical properties of materials by using photons to induce excited electronic states in the material system and analyzing the optical emission as these states relax. Typically, light is directed onto the sample for excitation, and the emitted luminescence is collected by a lens and passed through an optical spectrometer onto a photodetector. The spectral distribution and time dependence of the emission are related to electronic transition probabilities within the sample, and can be used to provide qualitative and, sometimes, quantitative information about chemical composition, structure (bonding, disorder, interfaces, quantum wells), impurities, kinetic processes, and energy transfer. [Pg.29]

In SXAPS the X-ray photons emitted by the sample are detected, normally by letting them strike a photosensitive surface from which photoelectrons are collected, but also - with the advent of X-ray detectors of increased sensitivity - by direct detection. Above the X-ray emission threshold from a particular core level the excitation probability is a function of the densities of unoccupied electronic states. Because two electrons are involved, incident and the excited, the shape of the spectral structure is proportional to the self convolution of the unoccupied state densities. [Pg.274]

VEM excitation energy relaxati( i. Such ways (channels) be probably chemisorption with charge transfer, production of phonons, ejection of electrons from surface states and traps, and the like. The further studies in this field will, obviously, make it possible to give a more complete characteristic of the VEM interaction with the surface of solid bodies and the possibilities of VEM detecting with the aid of semiconductor sensors. [Pg.343]

In alicyclic hydrocarbon solvents with aromatic solutes, energy transfer (vide infra) is unimportant and probably all excited solute states are formed on neutralization of solute cations with solute anions, which are formed in the first place by charge migration and scavenging in competition with electron solvent-cation recombination. The yields of naphthalene singlet and triplet excited states at 10 mM concentration solution are comparable and increase in the order cyclopentane, cyclohexane, cyclooctane, and decalin as solvents. Further, the yields of these... [Pg.82]

J.R. Bolton In solution most photochemical electron transfer reactions occur from the triplet state because in the collision complex there is a spin inhibition for back electron transfer to the ground state of the dye. Electron transfer from the singlet excited state probably occurs in such systems but the back electron transfer is too effective to allow separation of the electron transfer products from the solvent cage. In our linked compound, the quinone cannot get as close to the porphyrin as in a collision complex, yet it is still close enough for electron transfer to occur from the excited singlet state of the porphyrin Now the back electron transfer is inhibited by the distance and molecular structure between the two ends. Our future work will focus on how to design the linking structure to obtain the most favourable operation as a molecular "photodiode . [Pg.21]

These studies have allowed the spectroscopic identification of a number of electronically excited states of the metal oxides, but there appear to have been no analytical applications of the reactions to date. The emitting states, as summarized by Toby [14], are CaO(A n), SrO(ATl), PbO(a32+, b32+), ScO(C2II), YO(C2n), FcO(C ), A10(A2ni B2X+), and BaO(A i)1, D 2+). Nickel carbonyl reacts with ozone to produce chemiluminescence from an excited electronic state of NiO, which is probably produced in the Ni + 03 reaction [42, 43],... [Pg.359]


See other pages where Electron excitation probability states is mentioned: [Pg.354]    [Pg.200]    [Pg.336]    [Pg.295]    [Pg.291]    [Pg.332]    [Pg.432]    [Pg.188]    [Pg.209]    [Pg.2492]    [Pg.3026]    [Pg.443]    [Pg.262]    [Pg.300]    [Pg.66]    [Pg.140]    [Pg.360]    [Pg.177]    [Pg.52]    [Pg.357]    [Pg.168]    [Pg.16]    [Pg.429]    [Pg.281]    [Pg.73]    [Pg.159]    [Pg.4]    [Pg.128]    [Pg.47]    [Pg.103]    [Pg.473]    [Pg.683]    [Pg.16]    [Pg.55]    [Pg.69]    [Pg.70]    [Pg.72]    [Pg.73]    [Pg.73]    [Pg.66]    [Pg.374]    [Pg.123]    [Pg.64]   
See also in sourсe #XX -- [ Pg.303 ]




SEARCH



Electron excitation probability

Electron-excitation states

Electronic excitation probability

Electronic excited

Electronic excited states

Electronical excitation

Electrons excitation

Electrons, excited

Excitation probability

Probability electron

Probability electronic

Probability state

© 2024 chempedia.info