Big Chemical Encyclopedia

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

Articles Figures Tables About

Level shift operator

Here, of course, the Rtj i,j = S, T) are simply the matrix elements of the level shift operator between the isolated (discrete) states, S> and J>. That is... [Pg.275]

A(E) and f(E) are Hilbert transform from one another [7]. Since the lifetime of the quasi-bound state cj) is much longer than the lifetime of the relevant part of the continuum QH (f)), the Hermitian operators A(E) and f (E) are smooth functions within the energy range of interest. It results that the energy dependence of the level-shift operator can be neglected and that the effective Hamiltonian becomes energy independent... [Pg.9]

This energy independence appears as well in the previous model Hamiltonian when the quasi-continuum tends to a continuum (16). The Hermitian part of the level-shift operator is often negligible and was neglected in Eq. (24). Using Eq. (7) the lineshape can be expressed in terms of the poles of the Green function (see Section 2.2.2)... [Pg.9]

The effective Hamiltonian ff (z) is the sum of the projected Hamiltonian and of the level-shift operator [7]. For any initial state belonging to the inner space, the relevant information is contained in the resolvent projected, on the right, in the inner space. The dependence of W fz) on z can be reduced by time-filtering (see Section 2.2.1) or by extending the dimension of fhe inner space. P/(z-ff z) and Q/(z-H) are short-hand notations for fhe inversion of P z-W fz))P in fhe inner space and Q(z-H)Q in the outer space, respectively. If the initial state belongs to the inner space, the dynamics is obtained from the reduced resolvent... [Pg.44]

The derivation of the MCP formalism was detailed in the work of Hdjer and Chung [59] and one of the present authors (TZ) gave a comprehensive discussion of their derivation in the second chapter of his Ph.D. thesis [60], Interested readers should refer to those two works for a thorough exposition of this method while here, in the interest of brevity, we provide only the necessary information about MCP and focus on its level-shift operator, whose physical meaning needs more clarification. Following the same philosophy as the one behind the ECP, the MCP is naturally derived from all-electron atomic calculations at the Hartree-Fock level, and the final expression of the effective hamiltonian for the closed-shell valence electrons is... [Pg.214]

The quantity R in Equation 2.10 is called the level shift operator or self-energy and is given by... [Pg.23]

On integrating the integral (6.27) by contour analysis, it is necessary to continue analytically the matrix element of the level shift operator J s( ) from the first Riemann sheet through the cut onto the second sheet. This may be accomplished by defining the value of the level shift operator on the second sheet as... [Pg.135]

Level Shifting. This technique is perhaps best understood in the formulation of a rotation of the MOs which form the basis for the Fock operator. Section 3.6. At convergence the Fock matrix elements in the MO basis between occupied and virtual orbitals are zero. The iterative procedure involves mixing (making linear... [Pg.72]

The operation principle of these TFTs is identical to that of the metal-oxide-semiconductor field-effect transistor (MOSFET) [617,618]. When a positive voltage Vg Is applied to the gate, electrons are accumulated in the a-Si H. At small voltages these electrons will be localized in the deep states of the a-Si H. The conduction and valence bands at the SiN.v-a-Si H interface bend down, and the Fermi level shifts upward. Above a certain threshold voltage Vth a constant proportion of the electrons will be mobile, and the conductivity is increased linearly with Vg - Vih. As a result the transistor switches on. and a current flows from source to drain. The source-drain current /so can be expressed as [619]... [Pg.177]

In order to complete the calculation of the strong energy-level shift, one has to match at the accuracy 0(a) the particular combination of the non-relativistic coupling d d- Therefore we consider the scattering operator... [Pg.321]

The planner can indude the stock costs in addition to the other costs, but as a consequence delay costs are balanced with stock costs. Here this effect is not wanted at first high demand satisfaction is required. Keeping this to the maximum level, stock costs are lowered around this optimum. The trade off between production for future demands and inventory costs can be maximized by the so called shift operator. [Pg.82]

Settled dust Preliminary results on indoor and car dust show that levels of OPERs in dust collected in public buildings and cars are higher than the levels in dust collected from home environments [61, 68, 69]. There is also a shift in the OPER profile levels of TPP and TDC/PP increase moderately in the office dust, but a remarkable rise in TDC/PP levels is observed in car dust samples. Table 3 gives an overview of the sum of analyzed OPERs in the countries and the most dominant OPEs in the analyzed samples. Some of the aryl OPERs namely BDPP, DBPP, EHDPP were so far not detected in dust samples. There seems to be a region-specific consumption of OPERs as higher levels of, e.g., TPP and TDCiPP were observed in house dust from the USA and New Zealand ([15], [297]). [Pg.251]

Analysis of the products of field operators in these equations leads to a representation of the wave function and of the level shift in terms of diagrams of the type first introduced by Feynman. These diagrams provide a simple pictorial description of electron correlation effects in terms of the particle-hole formalism. [Pg.9]

The coupling to the continuum is implicitly contained in the second term in Eq. (376). The decay of the population in the bound state subspace is due to the imaginary part of P E — PHPY P. The contribution from the real part of P E — PHP) P, the so-called level shift due to the coupling to the continuum, can be neglected, if the energy dependence of the coupling term QHP is weak. In this case the second term in Eq. (376) can be regarded as a purely anti-Hermitian operator, and the effective Hamiltonian reduces to... [Pg.117]

Rationalisation rules. Rationalisation refers to the shifting of production from one site (or more) to another to achieve a more efficient level of operations. Under the UK NAP, a site was deemed to be eligible to benefit under the rationalisation rule if the operator could demonstrate... [Pg.58]

Starting from the gap Hamiltonian (33) and the interactions with the reservoirs (34) and (35), eliminating the reservoir degrees of freedom within the standard Bom-Markov approach we derive a master equation for the reduced density operator of the atomic ensemble. The calculation is lengthy but straight forward. Disregarding level shifts caused by the bath interaction we find for the populations in states cj ) the following density matrix equations in the interaction picture ... [Pg.219]


See other pages where Level shift operator is mentioned: [Pg.275]    [Pg.418]    [Pg.8]    [Pg.45]    [Pg.244]    [Pg.25]    [Pg.25]    [Pg.133]    [Pg.133]    [Pg.135]    [Pg.201]    [Pg.263]    [Pg.275]    [Pg.418]    [Pg.8]    [Pg.45]    [Pg.244]    [Pg.25]    [Pg.25]    [Pg.133]    [Pg.133]    [Pg.135]    [Pg.201]    [Pg.263]    [Pg.115]    [Pg.319]    [Pg.118]    [Pg.141]    [Pg.58]    [Pg.637]    [Pg.245]    [Pg.415]    [Pg.190]    [Pg.147]    [Pg.237]    [Pg.163]    [Pg.21]    [Pg.162]    [Pg.250]    [Pg.78]    [Pg.192]   
See also in sourсe #XX -- [ Pg.8 , Pg.44 ]




SEARCH



Energy level shift operator

Level shifting

Level, operating

© 2024 chempedia.info