Multiple-line spectra

The first compound studied, Nd2Sn2O7, has a multiple line spectra, and so the isotropic resonance of each spinning-sideband manifold was determined by integration over the whole signal, and was assumed to be the peak for which the first moment vanishes. Over a temperature range of 236 K to 350 K a linear relationship was found between chemical shift and reciprocal temperature, with a sensitivity of 22 ppmK at 236 K and 10 ppmK at 350 K ... 

Fig. 4. Radio frequency spectrum of H2 in the vicinity of the proton resonance frequency [4] in first clearly observed multiple line spectra with coherent radiation. The resonance frequencies are primarily determined by the interaction of the proton magnetic moment with the external magnetic field, but the states of different mj and mj are displaced relative to each other by the different values of the nuclear spin-spin and spin rotational interaction energies [4].

The electric quadrupole and magnetic dipole interactions both generate multiple-line spectra, and consequently can give a great deal of information. All three interactions can be expressed as the product of a nuclear term which is a constant for a given Mossbauer y-ray transition and an electronic term which can be varied and related to the chemistry of the resonant absorber being studied. 

Figure 2. A multiple-line spectrum typical of coupling of the unpaired electron to four equivalent protons as in the alanine radical, CH3CH3COOH. Nominal frequency 9.765 GHz.

Mehrheit,/. majority plurality multiplicity, mehr-kantig, a. many-sided, -kemig, a. polynuclear, having more than one nucleus. Mehr-korperproblem, n. niany-body problem, -kristall, m. polycryatal. -linienspektrum, n. many-line spectrum, mehr-malig, a. repeated, -mals, adv. several times, repeatedly. 

Vielling, m. Cryat.) multiple twin. Viellinienspektrum, n. many-line spectrum, viellinig, a. many-line, multilinear, viel-mal, adv. many times, -mehr, adv. much more, more. — conj. rather, -phasig, a. polyphase, multiphase, -polig, a. multipolar. 

Even small differences in the P-Cl bond lengths of chlorocyclophosphazenes give rise to a multiple line Cl NQR spectrum [309-314]. An increase in the P-Cl bond length is accompanied by a decrease in the C1 NQR frequency, and this most probably reflects an increased ionic character of the P-Cl bonds. Closely related chlorocyclophosphazenes show a linear relationship between CI NQR frequencies and P-Cl bond lengths [314]. 

In order to appreciate some of the variety of problems that can be aided with EC-EPR, it is necessary to understand the basic theory of EPR and the instrumentation required to perform an EPR experiment. It is also necessary to understand how an unpaired electron interacts with the atomic nuclei in a free radical, because this interaction produces the multiple lines characteristic of an EPR spectrum. The magnitude of the spacings of these lines can be related to the unpaired electron distribution in a free radical, so it is also helpful to have... 

Consequently, many more individual absorption processes can be accommodated on the frequency (energy) axis. Their actual number is indirectly proportional to the line-width. According to (9.2), the quantum of energy associated with the transition that would correspond to a single spectral line is sharply defined. Such a line spectrum is observed, for example, in atomic vapors. On the other hand, spectral lines of more complicated molecules, even in gas phase, are broader. This is due to the fact that the transition between two electronic states is complicated by the presence of multiple vibrational levels within each state. Furthermore, in the condensed phase, these vibrational levels are strongly affected by interactions with the surrounding molecules. 

The sensitivity of EPR to multiple coordination environments has been demonstrated in studies of Mn2+-doped CdS nanocrystals (63). In Mn2+ CdS nanocrystalline powders prepared by inverted micelle synthesis, four distinct resonances were observed and deconvoluted by varying experimental parameters including microwave power, microwave frequency, and temperature. The deconvoluted signals are shown in Fig. 18. Four distinct manganese species were detected through this experiment. A six line spectrum characteristic of isolated paramagnetic Mn2+ was observed at 300 K and below [multiline... 

F and so on, NMR spectra. When one of these spectra is examined, the various peaks or signals may be characterized by their position in the spectrum or chemical shift , the width of the peak, and the area under it. In addition, it is important to consider the possibility of multiple lines arising from a single nucleus. 

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