Notation space filling” model

Figure 3.17 Comparison between experiment (dashed curve) and calculations combining the polarizable continuum model for solute electronic structure and continuum dielectric theory of solvation dynamics in water. SRF(t) stands for S(t) in our notation. The calculations are for a cavity based on a space-filling model of Cl53, while the experiments are for C343. The two sets of theoretical results correspond to using water e(o>) from simulation (full curve) of SPC/E water and from a fit to experimental data (dash-dotted curve). (Reprinted from F. Ingrosso, A. Tani andJ. Tomasi, J. Mol. Liq., 1117, 85-92. Copyright (2005), with permission from Elsevier).

Draw the zigzag structure of heptane using simple line notation, and then use a molecular modeling program or a model kit to show that same structure as a space-filling model. 

For open-shell systems, therefore, the model space is no longer simple and sometimes not even known before the computations really start. For closed-shell systems, in contrast, the model space can be formed by a single many-electron state, which is taken as the reference state and which is sufficient in order to classify the single-electron states into particle (unoccupied) and hole (occupied or core) states, respectively. In open-shell systems, instead, the valence shells are neither empty nor completely filled. To facilitate the handling of such open shells, we shall provide (and discuss) a orbital notation in Subsection 3.4 which is appropriate for the derivation of perturbation expansions. 

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