Gaussian-shaped bands

FIGURE 12. Low-energy region of the (He I)PE spectrum of hexakis(trimethylsilyl)disilane (a) Gaussian-shape band deconvolution between 7.5 and 9.5 eV and (b) topological SiSi bond interaction model with radical cation state assignment... 

Here, T is the observed line width (Av << F), 7d is the peak-to-valley intensity in the difference spectrum, and To is the peak height of the Raman line. Although this equation is for Lorentzian-shaped bands, the results are approximately the same for Gaussian-shaped bands (the constant 0.385 becomes 0.350). In the case of carbon disulfide-benzene mixtures, the smallest shift observed was -0.06 cm-1, and the associated error was 0.02 cm-1 (77). A convenient rotating system that can be used for (1) difference spectroscopy, (2) normal rotating sample techniques (solid and solution), and (3) automatic scanning of the depolarization ratios as a function of the wave number has been designed (45). 

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)...

Figure 8. The component optical bands of the spectrum of UV-irradiated KN3 at room temperature obtained by fitting the total optical spectrum to gaussian-shaped bands.

Alternatively, absorption profiles of TM complexes can be obtained from a simple model. Instead of evaluating the half-bandwidths A1/2,/ for each electronic transition, Ai/2,/can be taken as empirical parameters (1,000-7,000 cm ), which depend on the CT characters of the electronic transitions higher CT character implies large A1/2 values and low CT character implies small A1/2 values. Then, an absorption profile is calculated as a sum of Gaussian-shaped bands using the following equation ... 

---