Equivalent states, chemically related

H. Bock and B. G. Ramsey, Angew. Chem., 85, 773 (1973) Angew. Chem., Int. Ed. Engl., 12, 734 (1973), report on the interpretation of the PE spectra of main group element compounds by comparison of equivalent radical cation states of chemically related molecules, based on MO perturbation arguments. 

A. Comparison of Equivalent States of Chemically Related Molecules 583... 

Principles for the interpretation of photoelectron spectra of silicon compounds (Sections II, IV and V) are as follows. Although the rather instantaneous ionization within 10 15 s does remove all difficulties concerning M 0 structure changes and specific M 0 state dynamics, still electronic relaxation is possible and especially the differences in the correlation of n electrons in M and n-1 in M 0 should not be neglected. Therefore, all PE spectroscopic information available on individual M 0 states (Section IV.B) should predominantly be used for their assignment. Last but not least, orbital models derived from simplified calculations should only be trusted, if their essentials can be substantiated by comparison of equivalent states within series of chemically related molecules9 (Section IV.A). 

Referring to the much recommended comparison of equivalent states of chemically related molecules 9 (cf. Figures 3 and 13 schemes 4, 8, 12 and 13), also for compounds of other elements like the recently PE spectroscopically characterized H3C-P=CH2113, advisable correlation with the ionization patterns of other iso(valence)electronic molecules like H3C-N=CH2 or H3C-C(H)=CH2 should always be preferred to fiddling around with nebulous d-orbitals. The answer to the title question is therefore straightforward no d —except as polarizing functions to improve basis sets for calculations of silicon compounds. 

The probability matrix plays an important role in many processes in chemical physics. For chemical reactions, the probability of reaction is often limited by tunnelling tlnough a barrier, or by the fonnation of metastable states (resonances) in an intennediate well. Equivalently, the conductivity of a molecular wire is related to the probability of transmission of conduction electrons tlttough the junction region between the wire and the electrodes to which the wire is attached. 

Equations 54 and 58 through 60 are equivalent forms of the fundamental property relation apphcable to changes between equihbtium states in any homogeneous fluid system, either open or closed. Equation 58 shows that ff is a function of 5" and P. Similarly, Pi is a function of T and C, and G is a function of T and P The choice of which equation to use in a particular apphcation is dictated by convenience. Elowever, the Gibbs energy, G, is of particular importance because of its unique functional relation to T, P, and the the variables of primary interest in chemical technology. Thus, by equation 60,... 

Since the state of a crystal in equilibrium is uniquely defined, the kind and number of its SE s are fully determined. It is therefore the aim of crystal thermodynamics, and particularly of point defect thermodynamics, to calculate the kind and number of all SE s as a function of the chosen independent thermodynamic variables. Several questions arise. Since SE s are not equivalent to the chemical components of a crystalline system, is it expedient to introduce virtual chemical potentials, and how are they related to the component potentials If immobile SE s exist (e.g., the oxygen ions in dense packed oxides), can their virtual chemical potentials be defined only on the basis of local equilibration of the other mobile SE s Since mobile SE s can move in a crystal, what are the internal forces that act upon them to make them drift if thermodynamic potential differences are applied externally Can one use the gradients of the virtual chemical potentials of the SE s for this purpose ... 

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