Series observations

These selection rules lead to the sharp, principal, diffuse and fundamental series, shown in Figures 7.5 and 7.6, in which the promoted electron is in an x, p, d and / orbital, respectively. Indeed, these rather curious orbital symbols originate from the first letters of the corresponding series observed in the spectrum. 

It is important to note that the ion series observed by the API-MS method may not be representative of all the products present, not the quantities thereof. Cleavage of the ethoxylate chain removes the capacity of silicone surfactants to be ionised and therefore detected by these methods. As such, for example, the cleaved silicone head group [M(D/CH2CH2CH2OH)M, 3] was never observed by API-MS. The nature of the API-MS process is such that competition between analytes for ionisation occurs, and as such compounds with higher surface activity and EO content can be expected to dominate in the resulting spectra. Suppression effects may thus preclude observation rather than confirm absence. As a consequence, the use of additional techniques such as FTICR-MS, GC-MS, HPLC and NMR to provide complementary data was also necessary. Furthermore, the high number of possible structures for each ion series observed, rendered it difficult to assign structures with confidence. Consequently simplified M2D-C3-0-(E0)n-R... 

Experiments were performed with various LiAl-X LDHs, with X = Br, NO3 and ISO4. As with the intercalation process, the nature of the anion exerts a powerful influence on the reaction. In the case of sulfate, the deintercalation reaction does not go to completion - only 40% of the available lithium sulfate was released. The deintercalation reaction initially proceeds very quickly, but the process is then halted. The rate of deintercalation is NOs" > Cl > Br . This series does not correspond with data on the anion selectivity for intercalation into Al(OH)3, which is S04 > Cl" > Br" > NO3". Neither is there a correlation of the release data with the heats of hydration of the anions. The series observed arises because the intercalation and deintercalation processes are a balance of a number of factors, including interactions between the guest ions and the host matrix. 

The above series in general is similar to the ligand nephelauxetic series observed in the case of d-transition metals. The greatest nephelauxetic effect has been observed in sulphides [46], cyclopentadienides [47], and oxides [48] of lanthanides. However, attempts to formulate a common and general nephelauxetic series for the lanthanide series have been futile using aquo ions as reference standards. In the case of lanthanide complexes with the same ligand in aqueous solutions, the absorption band positions of light and heavy lanthanides shift in different directions. This unusual behavior of complexes may be due to the differences in structure of aquo ions and the complexes. 

There exist time-series observations at two locations in the Caribbean South of Puerto Rico at the Caribbean Time-series Study site (CaTS 17.6°N, 67°W), and north of Venezuela at the CARIACO site (Carbon Retention in a Colored Ocean Project 10.5°N, 64.67°W). At the former, the Caribbean Surface Water (upper 75 m) experiences a yearlong influence of continental river input, as evidenced by lowered... 

Figure l6.6 Representative upper ocean profile of NO3, DON and PON at Station ALOHA based on 17-year time-series observations. Note accumulation of reduced N, especially DON in near-surface and decreases with depth. In the near-surface waters at Station ALOHA, DON accounts for nearly 95 % of the total fixed N inventory. 

Ocean, due to extremely low dissolved inorganic phosphate levels (Wu et al, 2000). Karl et al. (1997) found that diazotrophy increased in the subtropical North Pacific Ocean over seven years of time series observations in parallel with a decrease in soluble reactive P levels, suggesting a shift from N limitation towards P limitation. At some locations in the Baltic Sea, phosphorus additions show a significant impact on N2 fixation by cyanobacterial communities dominated by Nodularia, Aphanizome-non, and Anabaem (Fig. 38.12A). The level of observed stimulation of N2 fixation by P addition alone was equal to the simulation by P addition combined with Fe (Moisander et al., 2003). 

CHy Mass-resolved two-photon REMPI of CHj and CDj radicals, np, Rydberg series identified. Second Rydberg series observed and tentatively assigned to nf, E series 379... 

A fundamental observation of melt transport at mid-ocean ridges is that in both major and trace elements, MORBs are out of chemical equilibrium with the shallow upper mantle (e.g., see Kelemen et al, 1997, for review). One mechanism that has been suggested is that melt migration is localized into some form of channel network fed by porous flow at the grain scale. This basic idea has been incorporated into several different two-porosity models to try to reconcile U-series observations with those of stable trace elements. 

We think that the presented results nevertheless show the advantages of an approach that employs and merges water column observations and analysis of the sedimentary record to interpret time-series observations on the background of a much longer historical development of the ecosystem. 

Inert electrolytes show ion specificity, as discussed in Chapter 2 and illustrated in Figures 2.4, 2.5, 2.9, and 2.10. The anions affect the positive branches of the charging and electrokinetic curves, and the cations affect the negative branches. The affinity to particular monovalent anions and cations depends on the character of the surface, and follows the hard- soft acid-base principle that is, hard surfaces prefer to adsorb hard ions, and soft surfaces prefer to adsorb soft ions. The effects of ion specihcity on the charging and electrokinetic curves are usually minor. The affinity series observed in coagulation behavior are termed Hoffmeister series. 

The synthetic analogues, zeolites X and Y, have received considerable attention because of their value as industrial catalysts. This has seen virtually every cationic species from the Periodic fable introduced into FAU frameworks. The following is a listing of selectivity series observed ... 

Other series observed on natural samples were ... 

The series limit on which the autoionising resonances converge may or may not be stable. If the corresponding parent ion state can decay ra-diatively, then because radiative widths are (for low excitation energies) usually much smaller than autoionisation widths, the series observed is not much affected until high values of n. On the other hand, if the parent ion state itself lies above the double-ionisation threshold, it becomes susceptible to particle decay and acquires its own intrinsic width through autoionisation. 

The two major hydrocarbon series observed in this fraction are CnH2n-12 anc CnH2n-14 and acenaphthenes. Trace... 

Despite the widespread use of these eluotropic series, several workers have challenged their general validity and usefulness. Many studies have been reported in which it is quite clear that relative solvent strength can vary drastically for different samples [e.g.. Refs. (15-17) for some striking examples]. Similarly, the eluotropic series observed for different adsorbents often appear markedly different e.g., see the discussion of Ref. (7),... 

TOP instruments. Mechanisms are proposed for the formation of the ion peak series observed in the spectra, and the masses of fhe end-groups of fhese polymers can be inferred from fhe dafa. " " The fragment ions spectra obtained for PMMA and PS polymers are dependenf on fhe mass-to-charge rafio of fhe precursor ion, fhe mechanism of cation affachment, the nature of fhe cation, and fhe mobilfy of fhe polymer chain. " ... 

The ionization as anions of many commonly used anti-inflammatory agents is positively correlated with their biological action provided that ionization is not complete and that they are sufficiently lipophilic to reach their prostaglandin-inhibiting site of action. Examples include indomethacin 4.5) and the salicylates (Whitehouse and Dean, 1965). In the phenylindanedione 9.39) series, observation of the effect of varying the (on the anti-inflammatory action) pointed to a need for more accurate determinations of in the or Ao-substituted aryl derivatives, which are by far the most biologically active (van der B vgetaL, 1975). 

The P2p (1e and Sa ) ionization potentials were obtained by extrapolating the Rydberg series observed in photoabsorption (PA) spectra [26, 27] and by photoelectron spectroscopy in the X-ray region (XPS) [28 to 30]. Data for P2p3,2, P2pi/2, and P2p are shown below (compare also a 1980 review [31]) ... 

The mass spectra of the underivatized standards (Figure 3) provided further information about the location of the ethyl branch. For the tetraenes we have synthesized, there were always fragments at m/z 69, 83, and/or 97. (The next member of this series, m/z 111, was never observed, however). For each compound, the highest mass fragment of this series observed in the spectrum was consistent with cleavage at the 6 double bond, accompanied by a proton transfer (Figure 3). (The whole spectra for 1 and 2 appear in ( )). 

Human transferrin has also been used for Au cluster synthesis. Xavier et al. through MALDI TOF MS showed a broad distribution of Au nanoclusters ranging from Aujo-Auss with peak maxima at 22-33 Au. Between two separate series observed, major peaks are separated by miz 197 due to Au and the minor peaks are separated by mIz 32 due to sulfur. ... 

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