Fine spectrum

Define what is meant by the primary and secondary lines in a fine spectrum. 

A fine spectrum is an absorption or emission spectrum that displays a series of vertical fines indicating that only certain narrow wavelength bands (fines) are absorbed or emitted. A fine spectrum results when atoms are measured. This is the case because there are no vibrational levels in atoms, and therefore only very few transitions are allowed. 

He/Ne laser focussed into a small tapered hole in a pellet of the plastic. The flux density achieved at the focus was about 1000 Watts/cma. The scattered radiation was examined using a double spectrometer and photon-counting detection. A very fine spectrum, superior even to that of Maklakov and Nikitin (see Table 1), was recorded photo-electrically. Schaufele pointed out that a band atAv= 109cm-1 forecast previously by Tadokoro et aL (15) was not observed at first but in a note added in proof he mentions that a feature may be genuine at 98 2 cm-1. A band had already been observed at Av= 110cm-1 by instrument developers at the Cary Instrument Co. since Szymanski (16) shows a spectrum of isotactic polypropylene, recorded at Monrovia, Calif., on a laser sourced Cary 81 spectrometer, as an example of recent advances in Raman spectroscopy. 

Figure 6 shows the CTL spectra observed during the catalytic oxidation of ethanol on y-alumina, calcium carbonate, and barium sulfate. The profiles of these broad spectrum components are similar to each other, and they peak in the vicinity of 420 nm. The profiles of the CTL spectra from the excited species depend on the kind of catalyst. Fine spectra are observed in the non-porous BaSC>4 catalyst. In Fig. 6b, the thin curves denote the fine spectrum components obtained by the peak-fitting technique. 

Phosphors doped with rare-earth elements show two types of CTL spectrum, namely emission from the excited species and recombination radiation, simultaneously. Figure 21 shows the CTL spectrum from the TL-phosphor BaS04 Eu in air containing ethanol vapor. The emission band with fine spectrum components at 420 nm is attributed to the excited HCHO. The line spectrum components peaking at 580 and 615 nm are attributed to the electronic transitions within Eu3+ ions. 

FIGURE 1 Velocity calibration of a M ssbauer spectrometer. The spectrum shown (a) is of metallic iron at room temperature. Line positions are given in channels and line widths in mm/s. The velocity calibration constant (b) is derived from the known energy differences between various components of the magnetic hyper fine spectrum. In the present data a differential nonlinearity of about 1 percent is observed. Such spectrometer nonlinearity may become a source for significant systematic errors in high-resohition experiments. 

Fig. 3.5 The effect of a first-order quadrupole perturbation on a magnetic hyper-fine spectrum for a f transition. Lines 1,2 and 5,6 have equal separations only when there is no quadrupole effect acting, or when cos 0 =- 1 / 3.

As an example, Figure 14 shows the hyper fine spectrum of the D] line of sodium obtained 18 using this technique four components are visible, which are predicted between the two hyperfine sublevels (F = 0 and 1) of the ground level 3Si/2 hyperfine sublevels (F = 0... 

Bromine Hyper fine Spectrum NLIN Fitting... 

Basic computer codes such as one- and two-dimensional diffusion, S)f and Pi codes are being, revised to use toe JAERI-FAST >et. Codes for calculating a fine spec- trum and an ultra-fine spectrum in homogeneous media have been developed. Preparation of spectrum calculation codes for heterogeneous media is to progress. Development of a versatile computer code system is betog carried out to meet various requirements for reactor analysis. 

It is possible to understand the fine structure in the reflectivity spectrum by examining the contributions to the imaginary part of the dielectric fiinction. If one considers transitions from two bands (v c), equation A1.3.87 can be written as... 

Figure B2.5.12 shows the energy-level scheme of the fine structure and hyperfme structure levels of iodine. The corresponding absorption spectrum shows six sharp hyperfme structure transitions. The experimental resolution is sufficient to detennine the Doppler line shape associated with the velocity distribution of the I atoms produced in the reaction. In this way, one can detennine either the temperature in an oven—as shown in Figure B2.5.12 —or the primary translational energy distribution of I atoms produced in photolysis, equation B2.5.35.

For the variational calculations of the vibronic spectrum and the spin-orbit fine structure in the X H state of HCCS the basis sets involving the bending functions up to 0i = 02 = 11 with all possible and I2 values are used. This leads to the vibronic secular equations with dimensions 600 for each of the vibronic species considered. The bases of such dimensions ensure full... 

The distinction between in-plane A symmetry) and out-of-plane (A" symmetry) vibrations resulted from the study of the polarization of the diffusion lines and of the rotational fine structure of the vibration-rotation bands in the infrared spectrum of thiazole vapor. 

Transparent solid samples can be analyzed directly by placing them in the IR beam. Most solid samples, however, are opaque and must be dispersed in a more transparent medium before recording a traditional transmission spectrum. If a suitable solvent is available, then the solid can be analyzed by preparing a solution and analyzing as described earlier. When a suitable solvent is not available, solid samples may be analyzed by preparing a mull of the finely powdered sample with a suitable oil. Alternatively, the powdered sample can be mixed with KBr and pressed into an optically transparent pellet. 

The hydrogen atom and one-electron ions are the simplest systems in the sense that, having only one electron, there are no inter-electron repulsions. However, this unique property leads to degeneracies, or near-degeneracies, which are absent in all other atoms and ions. The result is that the spectrum of the hydrogen atom, although very simple in its coarse structure (Figure 1.1) is more unusual in its fine structure than those of polyelectronic atoms. For this reason we shall defer a discussion of its spectrum to the next section. 

A — P transition, shown in Figure 7.10(b), has six components. As with doublet states the multiplet splitting decreases rapidly with L so the resulting six lines in the spectrum appear, at medium resolution, as a triplet. For this reason the fine structure is often called a compound triplet. 

The UV spectrum of a complex conjugated molecule is usually observed to consist of a few broad band systems, often with fine structure, which may be sharpened up in non-polar solvents. Such a spectrum can often be shown to be more complex than it superficially appears, by investigation of the magnetic circular dichroism (MCD) spectrum, or by introduction of dissymmetry and running the optical rotatory dispersion (ORD) or circular dichroism (CD) spectrum. These techniques will frequently separate and distinguish overlapping bands of different symmetry properties <71PMH(3)397). 

Interatomic distances calculated from the detailed analysis of rotational fine structure of the UV spectrum of pyrazine are in close agreement with those observed in (7) and (8), with the calculated bond lengths for C—C of 1.395, C—N 1.341 and C—H 1.085 A (60DIS(20)4291). Thermochemical data have provided a figure of 75 kJ moP for the delocalization energy of the pyrazine ring (B-67MI21400). 

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