Multi-band-excitation

Leich, H., Deketelaere, S., Dbman, L, Dothey, M., and Wery. A new quantization technique for LSP parameters and its application to low bit rate multi-band excited vocoders. In EUSIPCO 1992). 

When several metal ion sites are present in a compound, population analysis can be carried out in two main ways. For Eu , since the intensity of the MD transition Do —> Fi is independent of the metal-ion environment, a spectral decomposition of the transition recorded under broad band excitation into its components measured imder selective laser excitation, followed by integration yields the population Pi of each site [31]. More generally, one can rely on lifetime measurement, since the luminescence decay will be a multi-exponential function which may be analyzed, for instance, with Origin , using the following equations ... 

In the sequential mode, excitation wavelengths for a given observation succeed each other. Emission wavelength can be fixed with a multi-band emission filter or synchronized with excitation part, using single-band emission filters. 

Diddams, S. A., Bergquist, J. C., Jefferts, S. R., and Oates, C. W. (2004). Standards of time and frequency at the outset of the 21st century. Science., 306, 1318-1324. Dirac, P. A. M. (1958). The principles of quantum mechanics. Clarendon Press, Oxford. Doherty, A. C., Lynn, T. W., Hood, C. J., and Kimble, H. J. (2000). Trapping of single atoms with single photons in cavity QED. Physical Review A, 63, 013401. Doljikov, V. S., Letokhov, V. S., Makarov, A. A., Malinovsky, A. L., and Ryabov, E. A. (1986). Raman probing of overtone and combinations band to study vibrational energy distribution produced by multi-photon excitation. Chemical Physics Letters, 124, 304-308. 

IB transitions create excitons, but these excitons are contained within either the VB or CB. This renders them useless for photovoltaic applications, which need to separate the charges across the band gap. They also ensure that at sufficiently high energies excitations are complicated, since these IB transitions occur in conjunction with SEs. This results in a multi-electron excitation that only creates one new electron-hole pair spanning the band gap. While formally these transitions are MEs, in photovoltaic applications they are equivalent to SEs. 

The Goeppert-Mayer two- (or multi-) photon absorption, mechanism (ii), may look similar, but it involves intennediate levels far from resonance with one-photon absorption. A third, quasi-resonant stepwise mechanism (iii), proceeds via smgle- photon excitation steps involvmg near-resonant intennediate levels. Finally, in mechanism (iv), there is the stepwise multiphoton absorption of incoherent radiation from themial light sources or broad-band statistical multimode lasers. In principle, all of these processes and their combinations play a role in the multiphoton excitation of atoms and molecules, but one can broadly... 

In conclusion, for most of the molecules discussed here and for others reported in the hterature (and for which full spectral characterization is available), the cross section of multi-branched chromophores is either found to scale linearly with the munber of branches or exhibit a small enhancement when the molecular size is increased (or the evidence for the enhancement depends on the choice of normahzation factors). The enhancement factor can be larger if cross sections at the same wavelength are compared, instead of the 3max values, if there is a change in the band shape or position. These factors could be relevant for applications that have limitations on the operational excitation wavelength. 

In this section we will consider the case of a multi-level electronic system in interaction with a bosonic bath [288,289], We will use unitary transformation techniques to deal with the problem, but will only focus on the low-bias transport, so that strong non-equilibrium effects can be disregarded. Our interest is to explore how the qualitative low-energy properties of the electronic system are modified by the interaction with the bosonic bath. We will see that the existence of a continuum of vibrational excitations (up to some cut-off frequency) dramatically changes the analytic properties of the electronic Green function and may lead in some limiting cases to a qualitative modification of the low-energy electronic spectrum. As a result, the I-V characteristics at low bias may display metallic behavior (finite current) even if the isolated electronic system does exhibit a band gap. The model to be discussed below... 

Figures 1.12 and 1.13 readily explain, without quantitative calculation, some key features of the photodissociation of H2O through excitation in the A and in the B absorption bands. Multi-dimensional potential energy surfaces are the cornerstones for a trustworthy analysis of molecular dynamics. Knowing the general topology of the PES often suffices for a qualitative explanation of the main experimental observations. However, in order to perform realistic calculations we need potential energy surfaces which are as accurate and complete as possible.

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