Isotopic branching

TABLE 3.3 Reactive cross sections for O ( d) + HD and isotopic branching ratio, /qd/OH. using different PESs. All results but the last one refer to QCT calculations... 

R. B. Turner, Isotopes Branch, United States Atomic Energy Commission Circular C-5, July, 1947. 

CPD took the diversification initiated with TRIUMF a step further in 1978, when it decided to move into production of radiopharmaceuticals (known as labelled or ta ed isotopes in the early days of CPD). For years CPD had supphed bulk isotopes to pharmaceutical companies. Now it decided that processing radioisotopes into compounds ready for medical use oflFered an opportunity for growth and profit that it could no longer ignore. The production of radiopharmaceuticals required more precision and stricter quality controls than the manufacture ofbulk isotopes, so in 1980 the isotopes branch created a special group to develop these products. 

In Hierl s model the very different isotopic branching of Ai+ and Ki+ is essentially attributable to the different electronic properties (ionization potentials) of these two species. Recently it has been demonstrated very directly how changing the electronic structure of one and the same ion affects its isotopic branching behaviour [27]. Vanadium ions were prepared using electron of different energy. 

Matsnmi, Y., Tonoknra, K., Inagald, Y., Kawasaki, M. Isotopic branching ratios and translational enCTgy release of hydrogtai and deuteriiun atoms in reaction of oxygen ( D) atoms with alkanes and alkyl chlorides. J. Phys. Chem. 97,6816-6821 (1993)... 

It is clear from Figure 6.8 that the band for each isotope is fairly symmetrical about the corresponding band centre and that there is approximately equal spacing between adjacent i -branch lines and between adjacent P-branch lines, with twice this spacing between the first R- and P-branch lines, R(0) and P(l). This spacing between R(0) and P(l) is called the zero gap and it is in this region where the band centre falls. 

Only the problem connected with channel (2d) was partly overcome in a previous CMB study78 by using a beam of isotopically labelled lsO, which permitted one to detect the HClsO product of channel (2d) at m/e = 31 (HClsO+) and 30 (ClsO 1 ), and to obtain an estimate of the branching ratio between channels (2a) and (2d) of 0.71 0.26, a value which is somewhat larger than any previous kinetic estimate, which gave values ranging from 0.44 to 0.55.81,85,86... 

The concentrations of the two isotopes on the phase-separation branches at the saturated vapour pressure is given by [5] and [6-8] ... 

In addition to the foregoing examples, periodate oxidation has been applied to isotopically labeled sugars (for the determination of label distribution), 226 -226 to certain branched-chain sugars,227-229 and to some nitrogenous derivatives of the simple sugars.230-236... 

Both branches end with the isotope 288Pb. The graph, similar to Figure 26-2, is drawn below. 

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