A Toy Model of Chemical Reaction Networks - TBI - Universität Wien

Appendix A
Parameters
The energy calculation in the Toy Model is parametrized in terms of ionization
energies I j and overlap integrals S ij of the usual Slater-type hybrid
orbitals. The parameters S ij needed for the energy calculation (see ch. 3)
have been obtained from the tables in [81], using the formulae for the overlap
of hybridized orbitals therein.
The bond lengths in tab. A.1, needed for this calculation were obtained
from the atom radii in [57, vol. III, sect. 3.1.1] and further refined by comparison
with [2].
Tab. A.2 lists the values of S ij that apply to σ overlaps of hybridized
orbitals that are oriented toward each other along a bond (upper left scheme
in Fig. 3.4) and to π overlaps between p orbitals. The overlap integrals S ij
depend only on the type and orientation of the involved orbitals.
In the current implementation, the overlap parameters are arranged in a
matrix S whose elements are lists of length 3. The rows and columns of the
Table A.1: Bond lengths depending on hybridization of bonding atoms. +
indicates guessed values.
H C N O
s sp 3 sp 2 sp sp 3 sp 2 sp sp 3 sp 2
H s 0.74 1.01 1.07 1.056 1.01 1.02 +1.01 0.96 0.97
C sp 3 1.54 1.52 1.46 1.47 +1.45 +1.43 1.43 +1.37
C sp 2 1.34 1.32 +1.33 1.29 +1.26 +1.29 1.23
C sp 1.21 +1.22 +1.19 1.15 +1.18 +1.12
N sp 3 1.40 +1.32 1.25 1.30 +1.26
N sp 2 1.24 +1.17 +1.22 1.18
N sp 1.10 +1.15 +1.11
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