Character state descriptions

This also ascribes a meaning to the other KS orbital energies. Without a reasonable description of the other ionization potentials, many excited state descriptions will fail because most excited states for molecules are of Rydberg character, or require some mixture of Rydberg character in their accurate description. 

The integrated block. This part of the course deals with the questioni What things can you do with character-analyses 7 Firstly, eight ready-made diagnostic descriptions are identified by means of keys. Then some more plants are described (from dried material) in a similar way, and comparable character states are put in a datamatrix. From this datamatrixare constructed a key for identification, a phenetio classification, and an attempt to the natural classification of these few plants only. The chapters IV and V of the manual are read in this part of the course. 

Ptychomnion cygnisetum is a nanandrous species hence character state coding of characters 1-25 refers to female plants only. Ramification type of P. cygnisetum could not be determined with certainty. Ramification seems to be monopodial, but in the material examined the older parts of the (female) plants are usually damaged or not collected. Occasionally, ramification shows some resemblance with sympodial branching. Hattaway s (1984) description of ramification is, unfortunately, inconclusive. Hence, the state of character 1 is coded as unknown for this species. 

Although Lewis structures of this type are not entirely adequate descriptions of the structure of the excited states, they do correspond to the MO picture by indicating distortion of chaige and the presence of polar or radical-like centers. The excited states are much more reactive than the corresponding ground-state molecules. In addition to the increased energy content, this high reactivity is associated with the presence of half-filled orbitals. The two SOMO orbitals in the excited states have enhanced radical, cationic, or anionic character. 

Strict requirement and can be theoretically met only if we know the underlying continuous function that provides the values of the derivatives at the time points of a discrete representation. The availability, though, of such a continuous function is based on a series of ad hoc decisions on the character and properties of the functions, and if one prefers to avoid them, then one must accept a series of approximations for the evaluation of first and second derivatives. These approximations provide a sequence of representations with increasing abstraction, leading, ultimately, to qualitative descriptions of the state and trend as follows (Cheung and Stephanopoulos, 1990) ... 

Hirata, S., Head-Gordon, M., 1999, Time-Dependent Density Functional Theory for Radicals. An Improved Description for Excited States With Substantial Double Excitation Character , Chem. Phys. Lett., 302, 375. 

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