Spectra computer-generated

Figure 2. Overlay of computer-generated spectrum of Nt at 1700 K (--------) onto...

The comparison shows that a part of the discrepancy between experiment and theory comes from the data analysis. The left wing of the simulated distfibution (filled bars) is not completely described by the LT9.0 analysis of the computer-generated spectrum (dashed line, mean of 0.282 nm). This may be a consequence of the shape of asiX), assumed in the LT analysis to be a log normal function, the interference of the o-Ps with the e" " lifetime distribution, and the low total o-Ps intensity of 9.0% for this material. 

The mean of the experimental hole-size distribution (solid line) is larger than the mean of the distribution from LT9.0 analysis of the computer-generated spectrum (0.282 nm, dashed line). From this behavior we conclude that a part of the total discrepancy seems, however, to have a more fundamental reason. We speculate that when trapped by a larger complex hole, o-Ps can move within this hole and concentrate at that part of the hole which shows the highest openness (size and three-dimensionality). Here the localized o-Ps finds its lowest energy level within the hole. Less open parts of this complex hole may then appear underrepresented. This possible effect is not considered in molecular modeling. 

Circular dichroism (CD) has also been used as a tool in determining the absolute stereochemistry of a side chain of a benzothiazine. The CD spectrum was compared against a computer-generated model <1999J(P1)149>. 

It should be noted that any comparison based purely on the computer generated power spectrum is inaccurate. A better comparison would be between the actual (/) j. 

A Fourier transform is the mathematical technique used to compute the spectrum from the free induction decay, and this technique of using pulses and collecting transients is called Fourier transform spectroscopy. A Fourier transform spectrometer requires sophisticated electronics capable of generating precise pulses and accurately receiving the complicated transients. A good 13C NMR instrument usually has the capability to do H NMR spectra as well. When used with proton spectroscopy, the Fourier transform technique produces good spectra with very small amounts (less than a milligram) of sample. 

MHz1H spectrum of compound 9-3 in Example 9.15. Figures 9.13a and b show, respectively, the computer-generated 60-and 250-MHz H spectra of structure 8-3 (Example 8.14), resulting from these input data ... 

FIGURE 8.5 Non-Lorentzian 23Na line shape from a solution of NaCl and malonyl gramicidin in lysolecithin micelles, (a) Experimental spectrum. (f>) Computer-generated Lorentizian components. FromVenkatachalam and Urry.92... 

At the empirical end of the spectrum of methods employed for the theoret-ical/computational generation of possible polymorphic crystal structures is the approach taken by Gavezzotti (1991, 1994a, 1996, 1997) and co-workers (1995,... 

The standard low-resolution mass spectrum (Fig. 30.3) is computer generated, which allows easy comparison with known spectra in a computer database for identification. The peak at the highest mass number is the molecular ion (M ), the mass of the molecule minus an electron. The peak at RA = 100%, the base peak, is the most abundant fragment in the spectrum and the computer automatically scales the spectrum to give the most abundant ion as 100%. The mass spectrum of a compound gives the following information about its chemical structure ... 

The computer-generated outputs from the mass spectrometer are similar to chromatograms obtained from other methods, and show peaks corresponding to the elution of particular components. However, it is then possible to select an individual peak and obtain a mass spectrum for the component in that peak to aid in its identification (p. 200). This has helped to identify hundreds of components present in a single sample, including flavour molecules in food, drug metabolites and water pollutants. 

Fig. 3 Computer-generated stick diagrams of the absorption spectrum of the V2 fundamental band of Hj at four different temperatures. Note the large number of lines at ca. 2500 cm and Q branch transitions with the band origin at 2521.3 cm . ...

Fig. 6 A computer-generated stick diagram of the Vj fundamental band for T = 30 K. This simple spectrum should represent absorption in dense clouds.

Fig. 7 A computer-generated stick diagram of the theoretical 2vj(2) - 0 emission spectrum at 1000 K. We used theoretical calculations communicated to us by J. K. G. Watson.

White noise, that is, noise consisting of a continuous spectrum of frequencies (or a computer-generated pseudo-random white noise), may be used as a perturbation signal in practical impedance measurements. However, single-frequency components obtained by the FFT have relatively low amplitudes and a long data acquisition time is necessary to... 

This can be done with a simple computer-generated mathematical formula (Roberts, 1996 Kristensen et al., 1995), which takes into account the absorption spectrum of the drug the output of the lamp source used in the experiments and the optical properties of the eye. The total relative number of photons absorbed by a drug under particular experimental conditions is the area under the product curve ... 

An important characteristic of a moderate resolution vibrational spectra of isolated molecules at higher excitation is its clump or bumpy structure (19). A computer generated example of what we mean is shown in Fig. 4. The spectrum consists of broad characteristic clumps or features. The breadth of the clumps is not due to experimental... 

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