Big Chemical Encyclopedia

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

Articles Figures Tables About

E„ transition

Color from Color Centers. This mechanism is best approached from band theory, although ligand field theory can also be used. Consider a vacancy, for example a missing CF ion in a KCl crystal produced by irradiation, designated an F-center. An electron can become trapped at the vacancy and this forms a trapped energy level system inside the band gap just as in Figure 18. The electron can produce color by being excited into an absorption band such as the E transition, which is 2.2 eV in KCl and leads to a violet color. In the alkaU haUdes E, = 0.257/where E is in and dis the... [Pg.422]

Most Fe complexes are octahedral but several other stereochemistries are known (Table 25.3). [FeX4] (X = Cl, Br, I, NCS) are tetrahedral. A single absorption around 4000 cm due to the T2 E transition is as expected, but magnetic moments of these and other apparently tetrahedral complexes are reported to lie in the range 5.0-5.4BM, and the higher values are difficult to explain. [Pg.1092]

We will limit ourselves to the surface segregation energy of an impurity of atomic number Z + 1 in a BCC matrix of atomic number Z and study the variation of this energy as a function of the number Nj of d electrons per atom in the d band of e transition metal Z. [Pg.376]

According to these transition state models2,. (y -products are formed via a chair (C) conformation where both the enolate and the imine are in E geometry (E,E) or via a boat (B) transition state where the enolate is in Z and the imine in Econfiguration C(E.E) or B(Z,E). antt-Products are formed via B(E,E) and C(Z,E) transition states. The transition states leading to 1 and 2 are based upon the more stable E geometry of the imine. For cyclic imines a complementary set of transition states can be applied based on the Z geometry of the imine. [Pg.759]

Friedly (F4) expanded the theoretical analysis of Hart and McClure and included second-order perturbation terms. His analysis shows that the linear response of the combustion zone (i.e., the acoustic admittance) is not sign-ficantly altered by the incorporation of second-order perturbation terms. However, the second-order perturbation terms predict changes in the propellant burning rate (i.e., transition from the linear to nonlinear behavior) consistent with experimental observation. The analysis including second-order terms also shows that second-harmonic frequency oscillations of the combustion chamber can become important. [Pg.54]

As discussed in Sect. 6.2, the electronic states of a paramagnetic ion are determined by the spin Hamiltonian, (6.1). At finite temperamres, the crystal field is modulated because of thermal oscillations of the ligands. This results in spin-lattice relaxation, i.e. transitions between the electronic eigenstates induced by interactions between the ionic spin and the phonons [10, 11, 31, 32]. The spin-lattice relaxation frequency increases with increasing temperature because of the temperature dependence of the population of the phonon states. For high-spin Fe ", the coupling between the spin and the lattice is weak because of the spherical symmetry of the ground state. This... [Pg.211]

Zn ->H +Zni, i.e. transition of electron from initially neutral H-atom into the interstitial ion of superstoichiometric zinc. According to Aishens and co-authors it is this formed Znt that is responsible for the... [Pg.141]

The type (e) transition for 4He is very useful as reference point at 2.18 K (normal-to-superfluid lambda transition). Such second orders are represented in Fig. 8.1. [Pg.193]

Conway, B. E., Transition from supercapacitor to battery behavior in electrochemical energy-storage, J. Electrochem. Soc., 1991, 138(6), 1539 1548. [Pg.139]

Schore, N. E. Transition Metal Alkyne Complexes Pauson-Khand Reaction. In Comprehensive Organometallic Chemistry II Abel, E. W., Stone, F. G. A., Wilkinson, G., Eds. Elsevier Oxford, 1995 Vol. 12, pp 703-739. [Pg.365]

The absorption spectram of Ti + ions in AI2O3 (shown in Figure 5.4) provides experimental evidence of the previously discussed splitting of d energy levels the broad band at aronnd 500 nm is a due to the t2g e transition. [Pg.155]

Dekker, E. Transition between laminar and turbulent flow in human trachea. J. Appl. Physiol. 16 1060-1064, 1%1. [Pg.317]

E and E. Transitions from the ground A, state to the E state is dipole allowed, but transitions to all the triplet states are spin-forbidden. The Aj Aj, and the Ai A2 transitions are electric dipole-forbidden but become allowed by vibrcnic coupling to the E level. A vibration of t or symmetry makes the former absorption allowed, while the latter is allowed only by a vibration of e symmetry. [Pg.10]

In the case of E, transitions, that is, those ocurring through the electric dipole mechanism, k=, and for an T /electron system with k= 1, in atomic units (which are used throughout, except in the figures, where the energy values are given in cm ). [Pg.275]

Another important quantity in the context of E transitions is the electric dipole line strength, defined as [7]... [Pg.275]


See other pages where E„ transition is mentioned: [Pg.1141]    [Pg.216]    [Pg.70]    [Pg.118]    [Pg.508]    [Pg.11]    [Pg.97]    [Pg.402]    [Pg.185]    [Pg.297]    [Pg.136]    [Pg.531]    [Pg.531]    [Pg.398]    [Pg.70]    [Pg.123]    [Pg.82]    [Pg.148]    [Pg.128]    [Pg.51]    [Pg.154]    [Pg.160]    [Pg.784]    [Pg.51]    [Pg.27]    [Pg.209]    [Pg.242]    [Pg.318]    [Pg.318]    [Pg.118]    [Pg.384]    [Pg.539]    [Pg.544]   
See also in sourсe #XX -- [ Pg.158 ]




SEARCH



E-A transitions

Mniopetal E synthesis plausible transition states

ORGANO-E(IV) COMPOUNDS OF TRANSITION METALS

Osborn, S.W. Lovesey, A.D. Taylor and E. Balcar, Intermultiplet transitions using neutron spectroscopy

Transition endo-E-syn

© 2024 chempedia.info