Tetramethylsilane, coincidence

Fig. 3.—Fourier-transform, Proton Magnetic Resonance Spectra45 of 6-Deoxy-l,2 3,4-di-O-isopropylidene-6-phthalimido-a-D-gaIactopyranose (54) (0.06 mg) at 90 MHz, Obtained by Transformation (N = 4,096) of the Free-induction Decay Signal (1,024 Datum Points, see Fig. 2), After the Appendation of 3,072 Zero, Datum Points ( Zerofilling, See Text), [(a) Spectrum associated with the real part of the transform, and (b) with the imaginary part (c) absorption-mode spectrum computed by phase correction of the spectrum in (a) and (d) dispersion-mode spectrum computed by phase correction of the spectrum in (b). Parameters for phase correction, A —255° and B —215°. Note that the phase of the tetramethylsilane and chloroform signals in (c) is slightly different from that of the carbohydrate derivative. By coincidence, the peak for residual water in spectrum (c) has almost the same intensity as the methyl signals, and could have been mistaken for one, had other spectra not been recorded.]...

Shifts are reported in this chapter using the lUPAC convention for 5, which coincides with the usual definition of the Knight shift in both cases signals that (in constant field) are at a higher frequency than the reference are assigned positive shifts, but they are plotted on the left-hand side of the spectrum. The conventional zeroes of the FI and scales are the signals from tetramethylsilane (TMS). Secondary standards have often been... 

The sensitivity of fragmentation to the nature of resonances was shown for tetramethylsilane by using the photoion photoion coincidence technique (Morin et al. 1986). In this technique, fragmentation channels are identified by the coincidences of pairs of ions in the time-of-flight mass spectrometer. For tetramethylsilane, two resonances were observed in the ion pair yield curves. The lower energy resonance, below the ionization edge, had been shown from electron spectra to decay into a one-hole state, but the production... 

After orienting the director of the liquid crystal relative to the gradient of the field (the gradient of the field may coincide with the direction of the average orienting field) the coefficients > and i j are calculated from the amplitude of the echo. This spin-echo method can also be applied to determine the diffusion coefficients of impurities in nematic liquid crystals (e.g., tetramethylsilane [103]). 

---