Double-frequency peak

An intense double-frequency peak appeared in each excitation spectrum since the LB film was very thin. All the complexes in Class 1 in LB film had the second largest excitation peaks near 266.0 nm, so this wavelength was selected as the excitation wavelength for the LB films, which was also selected as the excitation wavelength during the fluorescence lifetime measurement of the atypical rare earth complexes in LB films [10]. The second largest... 

First of aU, the observed 2vd harmonic band is anomalously sharp in comparison to the one theoretically calculated from the main D-band and does not have such a pronounced internal structure as the latter (Fig. 7.9a). Due to a presence of two maxima (around 1570 cm and around 1592 cm ) in the main G-band, one should expect three peaks in the 2vq harmonic band (two peaks corresponding to a doubled frequency of these two peaks and one peak corresponding to their sum) with a spectral interval of 22 cm. However, this is not the case even with consideration of a possible fine structure for the constituting bands. Relatively... 

A density matrix description of the polarization inversion process has been presented enabling the visualization of the role of the process in the suppression of zero-frequency peaks in SLF-2D NMR experiments based on the dipolar oscillations during CP. It has been shown that, during this process, a doubling of the amplitude of the Oscillatory component occurs accompanied by a reduction of the initial intensity of the non-oscillatory component to zero. 

Illustration of the TPPI method. The normal spectrum is shown in a, with peaks in the range -SWI2 to +SW/2. Adding a frequency of SW2 to all the peaks gives them all positive offsets, but some, shown dotted) will then fall outside the spectral window - spectrum b. If the spectral width is doubled all peaks are represented correctly - spectrum c. 

Measured (A) In-phase ( ) and quadrature (0) faradaic admittance polarograms at 1367 Hz. (B) Cot polarogram at 1367 Hz. (C) Faradaic admittance magnitude spec-trim near low frequency peak potential [at -1.605 V vs. Ag/Agl/(1.0 M TBAI, CH3CN)]. (D) Cot spectrum at -1.605 V vs. reference electrode. (ET Same as (B), except after interactive refinement of double-layer admittance subtraction. (F) Same as (A) after refinement of double-layer admittance subtraction. 

It is generally recognized that the stress response of the welded joints to ocean wave forcing is a wide-banded process with double spectral peaks. One of the peaks corresponds to the dominant wave frequency and the other is at the fundamental natural frequency of the structure. The stress spectrum which was proposed by Wirsching and Prasthofer [11], appears to be of the form... 

Let us start by illustrating the conceptual limitations of the double reptation idea. Consider the case of a polymer of high molecular weight at a volume concentration in a matrix of a polymer of much lower molecular weight. This case was considered in Section 6.4.4.2, and we found that the double reptation model predicts two relaxation peaks in G", a peak at a high frequency roughly equal to the inverse of the reptation time, g, of the short chains, and a low-frequency peak, whose frequency is the inverse of half the reptation time, T(Jl/2, of the... 

Ferry and co-workers observed that polyisobutylene exhibits double loss peaks in dynamic mechanical studies as a function of temperature and as a function of reduced frequency - "fast" Tg and "slow" T>Tg loss peaks. Similar mechanical loss peaks were reported for cis-trans- iny polybutadiene, both as a function of temperature " and frequency by Sidorovitch and co-workers. 

Besides the deviation mentioned above, the main problem with the dynamical information from the MF approximation is that it contains only one positive frequency and so the resulting real-time correlations cannot be damped or describe localizations on one side of the double well due to interference effects, as one expects for real materials. Thus we expect that the frequency distribution is not singly peaked but has a broad distribution, perhaps with several maxima instead of a single peak at an average mean field frequency. In order to study the shape of the frequency distribution we analyze the imaginary-time correlations in more detail. 

This mode corresponds to the IR peak associated with carbonyl stretch, used to identify the C-O double bond. Its predicted frequency is about 1810 (after scaling). This is in reasonable agreement with the experimental value of 1746. Using a larger basis set will improve this value. We ll discuss basis set effects in the next chapter. 

The infrared (IR) spectra of these compounds were mostly studied in the solid state which showed all the basic peaks characteristic of various functionalities attached to such bicyclic heterocycles with bridgehead nitrogen atoms. The difference in the frequency of carbonyl and carbon nitrogen double bond in tautomers of compound 18 (R = H) has been discussed previously in CHEC-II(1996) <1996CHEC-II(8)713>. 

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