Parent terms

Nomenclature based on a parent term with an appended suffix accounts for most natural product names. However, as related compounds are identified, or even when a suffix has to denote multiple functional groups, a variety of modifying terms can be employed. For example, the common prefix nor- denotes the removal of a skeletal atom from the parent structure the loss of two or more skeletal atoms is indicated by combining an appropriate numerical prefix with nor- , e.g., dinor- , trinor- (Giles 1999). Table 1.2 lists additional examples of commonly encountered modifying terms. 

One other point needs to be mentioned regarding the splitting of terms of the free ion in chemical environments, and this concerns the spin multiplicity. The chemical environment does not interact directly with the electron spins, and thus all of the states into which a particular term is split have the same spin multiplicity as the parent term. 

A magnetism below room temperature is governed by the lowest multiplet r7 (of the parent term 2Blg), and the presence of the excited multiplet r6 (of the parent term 2Aig) at 876 is irrelevant. 

The lowest crystal-field terms IR(parent terms), energy 2Eg(D, T2g), 0 2T2g(D), 0 2B2g(D, T2g), 0... 

The first two principles suggest that P(8j = 1) should be less than 0.5 for all j =, h and be smaller for higher-order effects. The third suggests that p(6) should incorporate effect dependencies such as that proposed, for example, by Chipman (1996). There (and in this chapter) the probability that a given term is active or inactive is assumed to depend on its parent terms, typically taken to be those terms of the next lowest order from which the given term may be formed. A higher-order term such as AlBq could have parents ALBL and Bq (the typical case), or have parents Ai and Bq. 

Fig. 18.4. The excitation photon emissivity coefficient for C II (2s23s2S-2s22p2P) at 858 A, driven from the ground term 2s22p2P. The emissivities are calculated in the GCR picture and so there are equivalent entries in the database for emissivities driven by excitation from the metastable 2s2p2 4P and by recombination (free electron capture) from 2s2 4S and 2s2p3P and by charge transfer - also from the latter two parent terms...

The 5f, 6d, and 7s electrons of the elements from actinium to curium, all having about the same energy, produce many low levels. The spectra are complex, and analysis is complicated by the existence of two sets of low parent terms built on P and P d, having opposite parities and responsible for two almost independent sets of transitions. Within the past several years considerable progress has been made in the analysis with the aid of new data, especially Zeeman data, and the further help of theoretical predictions. It is now possible to describe the variation of binding energies of different types of electrons as a function of atomic number and degree of ionization, which can be correlated with chemical behavior. 

For modern Westerners however, even a junior partnership is a better deal than childlike subservience notice how Maria Sabina s message is couched in parental terms ... 

Because of their aromatic-like reactivity the dihydrodiazepinium salts were described as quasi-aromatic compounds, a term which had previously been used to describe nonaromatic compounds which none the less showed aromatic chemical properties.47 More recently it has been suggested5 6 that the tendency to undergo substitution rather than addition reactions might be termed meneidic or regenerative rather than quasi-aromatic owing to the confusion of the parent term aromatic. Dihydrodiazepinium salts are thus examples of compounds having meneidic or regenerative character. 

There is only a single parent term dA, 5D) that interconnects the children terms ds, 6S) and d5, AP) then the relevant coefficients of fractional parentage, according to Table 8.42, are... 

The number of the progeny terms F/ can be exactly determined by the methods of group theory. It depends on the L value of the (parent) term L and on the symmetry of the ligand system Number of progeny terms ( = f... 

These building blocks can be combined into nets (or networks) where the net, whether 1-, 2- or 3-dimensional, is sometimes called a coordination polymer if it is held together by metal-ligand or coordination bonds. For the 3D-case, metal-organic frameworks can be used. The acronym MOF for metal-organic framework should be avoided since the parent term is not yet well established and there seem to be no great need for an abbreviation in the context where it is used. 

The weight of the different parent terms > in the ground state wave function is given by the coefficients of fractional parentage (cfp) Q. When the sudden approx-... 

The energy of each term with respect to the barycentre of the parent term can be approximated by Equation 1.24. 

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