Spectral approach

Figure C3.1.1. The basic elements of a time-resolved spectral measurement. A pump source perturbs tlie sample and initiates changes to be studied. Lasers, capacitive-discharge Joule heaters and rapid reagent mixers are some examples of pump sources. The probe and detector monitor spectroscopic changes associated with absorjDtion, fluorescence, Raman scattering or any otlier spectral approach tliat can distinguish the initial, intennediate and final...

COSTELLO, C.E., Application of tandem mass spectral approach to structural determination of saponins. In Advances in Experimental Medicine and Biology (G. R. Waller and K. Yamaski, eds.), 405, Plenum Publishing, New York. 1996, pp. 317-329... 

Fully Coupled Six-Dimensional Calculations of the Water Dimer Vibration-Rotation-Tunneling States with a Split Wigner Pseudo Spectral Approach. 

Tsukahara, Y., Nakaso, N., and Ohira, K. (1991). Angular spectral approach to reflection of focussed beams with oblique incidence in spherical-planar-pair lenses. IEEE Trans. UFFC 38, 468-80. [149]... 

Finally, it should be noted that other spectral analyses such as Raman, nuclear magnetic resonance, and fluorescence spectroscopies, which are correlated to more local chemical entities or individual atoms in the molecular systems, complement the CD data. Although other spectral approaches may provide more effective tools for analyzing a local structure or individual atoms in the molecular systems than the CD does, the CD approach is indispensable for the estimation of change or population in chiral structures on the average. 

Blake RD, Massoulit J, Fresco JR (1967) Polynucleotides VIII. A spectral approach to the equilibria between polyriboadenylate and polyribouridylate and their complexes. J Mol Biol 30 291-308... 

Next we will utilize the sum over states or spectral approach when we assume that it is possible to determine an exact reference state 0) together with eigenfunctions, n>, that are solutions to a Hamiltonian given by Ho + Wse- Using this basis of exact states and that the energy difference between the state given by n> and the reference state 0> is given asco = E - Eq, we are able to write the linear response function as... 

The structure of liquid silicates suggested in the last few sections was presented as a reasonable interpretation of conductance, viscous flow, and density measurements and the variation of the heats of activation with composition, for example. What evidence for the chains, rings, and icebergs is given from spectral approaches such as Roman and NMR If all is well in the earlier interpretation, it should be possible to see evidence of the structures in the spectral peaks. 

Although this spectral approach has had but limited application thus far, it appears to have great promise for exploring the topology of proteins. 

We now discuss the study of stability of two-dimensional flows of two viscoelastic fluids by a spectral approach. (See Figure 7.)... 

Optimally, the "analytical" and the "spectral" approaches should be combined. The two are complementary and together provide the most insight into the behavior of a UV filter or a sunscreen preparation. 

A different case is the photoenolization of ortho-hydroxybenzoyl derivatives, as outlined in Fig. 7. Here we see there is practically a total reconversion back to starting material at a very fast rate, leading one to conclude that there is total photostability. The same conclusion would be reached whether one is using either a normal specific analytical (e.g., HPLC) or the simple spectral approach. Special photophysical equipment is needed to observe these very short-lived photo-enol transformations. 

C. Leforestier, L.B. Braly, K. Liu. M.J. Elrod and R.J. Saykally, Fully coupled six-dimensional calculations of the water dimer vibration-rotationtunneling states with a split Wigner pseudo spectral approach, J. Chem. Phys., 106 (1997) 8527-8544. 

These two examples show the utility of the spectral approach or establishment of the chemical profile of the body fluids that can now be achieved with high-resolution analyzers. Chemical indicators of abnormal states can be found without prior knowledge of their existence and, thus, without having to decide which specific chemical indicators are to be investigated. 

Druskin, V., and L. Knizhnerman, 1994, Spectral approach to solving three-dimensional Maxwell s diffusion equations in the time and frequency domains Radio Science, 29, No. 4, 937-953. 

Thus, in the spectral approach, wavefield extrapolation from one horizontal level to another is implemented by multiplying its spectrum by the complex conjugate of the vertical derivative of the spatial spectrum of the Green s function for the Helmholtz equation. 

In areas with an irregular coastal configuration, the wave height is calculated on the basis of a method developed by Druet et al. (1976a) and based on a spectral approach to the sea state. 

Estimates of IVR rates have also been inferred from spectral studies. The principal spectral approach, the measurement of the emission spectra of isolated molecules (for a review, see, for example, Ref. 3), relies on the fact that the spectral characteristics of emission from a molecule will depend intimately on the vibrational character of the excited molecular state. If one prepares a gaseous molecule in a well-defined vibrational state and subsequently observes emission bands that would not be expected to arise from this initially prepared state, then some IVR process can be inferred. Moreover, a rate can be calculated for the process by comparing the intensities of expected emission bands (vibrationally unredistributed emission) and unexpected emission bands (vibrationally redistributed emission). Redistributed and unredistributed emission often are loosely termed relaxed and unrelaxed. Since energy is conserved in isolated molecules, there is no real energy relaxation, as occurs in solution or in solids. 

Leforestier C, Braly L B, Liu K, Elrod M J and Saykally R J 1997 Fully ooupled 6-dimensional oaloulations of the water dimer VRT states with a split Wigner pseudo-spectral approach J. Chem. Phys. 106 8527-44... 

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