Doublet method

As a result we can measure the effect which is 10 times larger than that in the alkali doublet method, have 100 larger statistics, cover a large range of red-shifts/cosmological time and have better control of the systematic errors. 

The mass determination of ionic species (atomic or polyatomic ions) in mass spectrometry is always a comparative measurement, which means the mass of an ionic species is determined with respect to reference masses of elements (or substances) used for mass calibration. The reference mass is thus acquired from the mass unit (m = In = 1/12) of the mass of the neutral carbon isotope (m = 1.66 X 10 kg). A mass calibration is easy to perform in solid-state mass spectrometry if the sample contains carbon (using carbon cluster ions with whole masses, as discussed above). The so-called doublet method was apphed formerly, e.g., ions and doubly charged Mg + forming a doublet at the same nominal mass number 12 were considered, where they are slightly displaced with respect to one another. The doublet method is no longer of relevance in modern inorganic mass spectrometry. Orientation in the mass spectra can be carried out via the matrix, minor and trace elements after mass calibration and by comparing the measured isotopic pattern of elements with theoretical values. 

Roberts PM, Phillips WS, FehlerMC (1992) Development of the active doublet method for measuring small velocity changes and attenuation in solids. J Acoust Soc Am 91 3291-3302... 

WFth all semi-empirical methods, IlyperChem can also perform psendo-RIfF calculations for open -shell systems. For a doublet stale, all electrons except one are paired. The electron is formally divided into isvo "half electron s" with paired spins. Each halfelec-... 

Is2s3s. Not all three-eleetron eonfigurations have both quartet and doublet states for example, the Is 2s eonfiguration only supports one doublet state. The methods used above to generate S = 3/2 and... 

L. Lederman (Batavia, Illinois), M. Schwartz (Mountain View, California) and J. Steinberger (Geneva) for the neutrino beam method and the demonstration of the doublet structure of the leptons through the discovery of the muon neutrino. 

NMR is the method of choice for determining the ratio of EO units to PO units since the analysis is simple to perform, does not require calibration, and is applicable over a wide range of EO-PO ratios. The spectrum contains only two resonances a doublet due to the methylene groups of the PO units, and a composite band, which is due to the CH2O groups of the PO and EO... 

About twenty-five molecules (all containing a methyl group) have been studied by the doublet splitting method. The barrier values obtained are given in Table I, along with values obtained by the thermodynamic method where available. In several of these molecules, independent barrier values were obtained from a number of spectral lines for each of several isotopic species, with agreement to 5 per cent or better. While some systematic error can still be present (for example, from an error in the stucture ), the... 

An important feature of photodetachment methods is that the selection rule for electronic transition is A5 = +1. Therefore, photodetachment of (doublet) negative ions... 

If the spin-spin information was being transmitted by the normal through-bond mechanism the upfield three proton signal would be expected to occur as a doublet because these protons are the only ones which can assume the required planar zig-zag conformation 77>78h Preliminary results, using the change in chemical shift method 79>, indicates that the energy barrier to rotation is of the order of 20 k.cal.mole O. As expected the silicon compound (39) shows a nine proton doublet... 

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