Isotope lowest

The full quantum mechanical study of nuclear dynamics in molecules has received considerable attention in recent years. An important example of such developments is the work carried out on the prototypical systems H3 [1-5] and its isotopic variant HD2 [5-8], Li3 [9-12], Na3 [13,14], and HO2 [15-18], In particular, for the alkali metal trimers, the possibility of a conical intersection between the two lowest doublet potential energy surfaces introduces a complication that makes their theoretical study fairly challenging. Thus, alkali metal trimers have recently emerged as ideal systems to study molecular vibronic dynamics, especially the so-called geometric phase (GP) effect [13,19,20] (often referred to as the molecular Aharonov-Bohm effect [19] or Berry s phase effect [21]) for further discussion on this topic see [22-25], and references cited therein. The same features also turn out to be present in the case of HO2, and their exact treatment assumes even further complexity [18],... 

Even at the lowest temperatures, a substantial pressure is required to soHdify helium, and then the soHd formed is one of the softest, most compressible known. The fluid—soHd phase diagrams for both helium-3 and helium-4 are shown in Eigure 1 (53). Both isotopes have three allotropic soHd forms an fee stmeture at high pressures, an hep stmeture at medium and low pressures, and a bcc stmeture over a narrow, low pressure range for helium-4 and over a somewhat larger range for helium-3. The melting pressure of helium-4 has been measured up to 24°C, where it is 11.5 GPa (115 kbar) (54). 

Table I. The Lowest Level of Each Configuration of Pu I and Pu II with their Corresponding Lande g-Values and Experimental Isotope Shifts (E in cm-l and IS in 10-2 cm-l).

The cocondensation of nickel atoms and CS2 at 12 K resulted in the formation of three binary, mononuclear, nickel/CS complexes, NKCSjln, n = 1-3 (145). Mixed CS2/ CS2 isotopes were used to identify the lowest stoichiometry species. An interpretation of the IR and UV-visible spectra, as well as normal-coordinate analyses (144), suggested that these species are best considered as normal 7r-complexes, with the nickel atom coordinated to the C=S bond in a manner analogous to C=C bond coordination (123). 

The radiochemistry of ruthenocene has been studied by Baumgartner and Reichold (9) and by Harbottle and Zahn (29). It is found that neutron irradiation of crystalline RuCp2 yields about 10% of the radioactive ruthenium as RuCp2- More specifically, an isotopic difference in the radiochemical yield is found Ru, 9.6 0.1% Ru, 10.7 0.2% and Ru, 9.9 0.2% (29). In liquid solution the isotopic effect is much more pronounced, although the yields are lower. This was suggested by Harbottle as a general principle the greatest isotope effects are associated with the lowest yields. While this principle has not yet been substantiated, it seems reasonable since any thermal reactions which may increase the yields would not likely show any isotope effect. 

The analytical detectability applying a CL method should, in principle, be comparable to that obtained using radioactive labels, without all the disadvantages related to the use of isotopic labeling. In fact, assuming reasonable values for the quantum efficiency of the chemiluminescent reaction (Cl 0.01), for the overall photon collection efficiency of the optical system-CCD camera assembly (T) 0.01%), and for the intensity of the lowest detectable CL signal (about... 

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