Absorption spectra with Gaussian

Figure 5. Absorption spectra with Gaussian resolution for terminally bound and bridging azide model complexes and for met-azlde hemocyanin.

The average depolarization lifetimes t, plotted as open circles versus pump-probe wavelength in Fig. 2, increase from 5 to 12 ps as the wavelength is tuned to the blue from 675 to 660 nm. We have simulated this dependence by modeling the PS I core antenna absorption spectrum with Gaussian curve analysis of the Chi a Qy absorption spectrum of highly enriched PS I particles [7]. According to Forster theory, EET from Chi a spectral component i to spectral component j in the core antenna will occur with rate proportional to... 

The calculated and experimental absorption spectra are shown in Fig. 2. The absorption spectrum is obtained by broadening the theoretical line spectrum with Gaussian function using two different broadening parameters. 

Cis-cis- TOoCl (NH3) (en) ]+ — The absorption and CD spectra in DMSO for the isomer derived from (+)5---[Co(C03)-(NH3)2(en)]+ are shown in Figure 2, where the vertical lines represents the results of the Gaussian analysis of the absorption spectrum, with labels specifying the excited states of the tetragonal components. The CD spectrum shows dominant negative peak at 16,230 cm- , which corresponds closely to the position of the... 

The oscillator strength for absorption is a very important quantity signifying the nature of the transition. If the absorption spectrum is known, the oscillator strength can be calculated using Eq. (4.20). Instead of numerical integration, one often assumes that the spectrum is approximately gaussian with the same half-width Av (cm-1) as experimentally observed. One then obtains/, the oscillator strength, as... 

Figure 23-8 Resolution of the visible circular dichroism (ellipticity) spectrum (A) and absorption spectrum (B) of the Pseudomonas blue protein into series of overlapping Gaussian hands (—). The numbers 1 to 6 refer to hands of identical position and width in both spectra. Absorption envelopes resulting from the sum of the set of overlapping Gaussian bands (—) correspond within the error of the measurement to the experimental spectra. The dashed part of the CD envelope above 700 nm was completed by a curve fitter with the use of a band in the position of hand 1 of the absorption spectrum. From Tang et al.68...

Figure 4. Spectrum of the two-photon absorption coefficient P in cm/MW for PDN6S, calculated from birefringenece growth curves as a function of two-photon energy ( ) compared with single-photon absorption spectrum (- - -). Solid line is a least-squares fit to p using the sum of two Gaussians, one broad ( 412 meV), the other narrow ( 33 meV). (Reproduced with permission from Ref. 8. Copyright 1990 Elsevier Science Publishers.)...

CV at 30 K should be composed of two electronic transitions from one ground state to split two Si states. In fact, this prediction is consistent with the experimental observation (Fig. 6) that a shoulder remained at a higher-energy side of the absorption maximum. For these reasons, we fit two Gaussian curves on the absorption spectrum at 30 K. On the other hand, two ground states, each of which has Si state split into two electronic states, exist together at room temperature. Thus, the absorption spectrum at room temperature should be composed of four Gaussian curves [69],... 

Figure 4. A) Room-temperature optical spectrum of a single crystal of plastocyanin obtained with light incident on the (0,1,1) face and polarized parallel (solid line) and perpendicular (dashed line) to a (from Ref. 11). B) Gaussian resolution of the 35 K visible absorption spectrum of a plastocyanin film with suggested assignments the symbols ( ) represent the experimental absorption spectrum. Right plastocyanin unit cell projected on the (0,1,1) plane, showing the positions of the four symmetry-related Cu atoms at their first coordination shells.

The theoretical 4f10 - 4195d absorption spectrum of Ho3+ in YLF is calculated and compared with the experimental excitation spectrum (Wegh et al., 1998) in fig. 32. Each level was convoluted by a Gaussian function with 0.1 eVFWHM. Although the 4f10 4f95d transition... 

The theoretical absorption spectra of Eu2+ at all three sites in BAM were obtained by broadening the oscillator strengths by a Gaussian function with 0.3-eV FWHM. The calculated spectra in comparison with experimental excitation spectrum are shown in fig. 37. In the experimental excitation spectrum, three main peaks (a-c) and one sub-peak (b7) are clearly identified. The spectmm of the BR site has only one peak whereas the spectra of the aBR and mO sites have two peaks each. For easy comparison, a tentative spectrum consisting of 1 1 1 contribution of each spectrum is also shown in the figure. In this tentative theoretical absorption spectrum, all main features of the experimental spectrum are reproduced without using any empirical parameters. 

Fig. 5 Electronic transitions of [Re(Cl)(CO)3(bpy)] calculated in vacuum (a), acetonitrile (b), simulated absorption spectra in vacuum (c, dashed) and acetonitrile (c, full), and experimental absorption spectrum measured in acetonitrile (d). It follows that successful TD-DFT simulation of the absorption spectrum and singlet CT states requires using hybrid functionals and continuum dielectric models for the solvent [11, 33], Calculation TD-DFT G03/PBE0, CPCM for MeCN. Simulation All calculated transitions included. Gaussian shapes (jwhm = 0.4 eV cm- ) of the absorption bands are assumed. Band areas are proportional to calculated oscillator strengths. Simulated using the GaussSum software. Reprinted with permission from [33]...

Fig. 1 Top Behavior of the electronic linear chiroptical response in the vicinity of an excitation frequency. Re = real part (e.g., molar rotation [< ]), Im = imaginary part (e.g., molar ellipticity [0]). Without absorption line broadening, the imaginary part is a line-spectrum (5-functions) with corresponding singularities in the real part at coex. A broadened imaginary part is accompanied by a nonsingular anomalous OR dispersion (real part). A Gaussian broadening was used for this figure [37]. Bottom Several excitations. Electronic absorptions shown as a circular dichroism spectrum with well separated bands. The molar rotation exhibits regions of anomalous dispersion in the vicinity of the excitations [34, 36, 37]. See text for further details...

The intriguing observation 17) that absorption maxima of [4,4,2]-propellanediones 1,2, and 3 depended markedly on the presence of remote unsaturation has stimulated considerable activity. As summarized below, the saturated compound 1 had an absorption band of Gaussian shape with maximum at 461 nm, the most intense maximum of the diene 3 was at 537 nm with fine structure at shorter wavelengths, and the morioene 2 gave a composite spectrum. This remarkable effect was originally... 

Figure 7 Complete set of 45 bands required to fill the absorption and MCD band envelopes of the phthalocyanine-rmg-reduced radical anion species [ZnPc(—3)] . The absorption spectrum was recorded at 77K, and the MCD spectrum at 40K. The bands were fitted using Gaussian-shaped bands with the identical band centers and bandwidths for pairs of absorption and MCD bands. A weak, Faraday term located at 14 860cm is due to a residual 1% impurity of neutral ZnPc(—2). Experimental data (sohd fine) fitted data (broken line). (Reproduced with permission from J. Mack, Y. Asano, N. Kobayashi, M. J. Stilhnan (2005) J. Am. Chem. Soc. 127 17697-17711. 2005 American Chemical Society)...

The current best resolved absorption spectrum of the ascorbate anion radical (Figure 1) was determined (26) in a study of ascorbate oxidation by halide anion radicals (particularly Br2") at pH 11. The spectrum shows a symmetrical Gaussian-type band with an absorption peak at 360 nm and a width at half-maximum of about 50 nm. The molar absorbance at 360 nm = 3300 M cm" is lower than earlier reported values 21,23). 

First, either a Lorentzian or Gaussian filter is applied to the FID to reduce the amount of noise. The choice of lineshape will depend on the shape of the frequency domain spectrum, the lineshape is related to how the fluorine spins interact with their environment. The filter linewidth is generally similar to or slightly less than the T2 value (T2 can be estimated from the spectral linewidth). After application of the time domain filter, a fast Fourier transform (FFT) is performed. The resultant frequency domain spectrum will then need to undergo phase adjustment to obtain a pure absorption spectrum. The amount of receiver dead time (time lost between the end of the excitation pulse and the first useful detection time point) will determine the presence and extent of baseline artifact present as well as how difficult phase adjustment will be to accomplish. 

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