Compound Morse potential

Figure 1. Compound Morse potentials of the form employed by Tsai and Trevino [1-3] to simulate energy release arising from chemical reaction. Energy and bond length are in arbitrary units.

Fig. 2b is a compound Morse potential for simulating the exothermic dissociation of a hypothetical diatomic molecular crystal of A2 A2 = A+A+energy. A form of this potential was used in problem (3) for studying the profile of a detonation wave. In this potential ... 

Figure 11.1 Morse potential energy curves for CC14 and CH2C12, DEC(l) compounds.

Figure 11.7 Morse potential energy curves for C6F5C1 and C6F6, Eql(2/2) compounds. Calculated from electron impact, ECD, and TCT electron affinities.

With the Ea of the molecules and radicals, bond dissociation energies, and electron impact data, the Morse potential energy curves for the C6F5X compounds can be calculated. They are shown in Figures 11.7 and 11.8. There are two curves dissociating to each of the complementary limits C6F5 + X(—) and C6F5(-) + X. The... 

The temperature dependence of negative-ion mass spectra of environmental compounds has been analyzed in terms of the electron affinities and EDEA values. Morse potential energy curves have been constructed using the Herschbach parameters to illustrate the different types of thermal electron reactions. The temperature dependence of the ECD response for chlorinated naphthalenes and biphenyls has been predicted and is compared with experimental data for several pesticides and chlorinated biphenyls. 

This method should lead to results which are just as accurate as the results of the methods described in the previous sections, and can be used as a check on the computed potential-energy minimum E(R ) at R = Re if fl is determined from curve-fitting of the Morse potential with the computed R and De and this leads to a wrong we and/or w, then it can be assumed that De and/or Rg are/is wrong. It is to be emphasized (12) that the Morse curve can mostly not be used with essentially ionic compounds like NaF because the attraction given by the Coulomb term extends out in space to greater distances than the Morse exponential part for these compounds many other types of potential have been postulated (e.g. the Hellmann-potential or the Bom-Landd potential (77)). The reader can try to calculate cog, etc. of NaF from the SCF— LCAO—MO calculation of Matcha (72) in the Roothaan-Hartree-Fock approximation, using the Morse curve (E = —261.38 au, R =3.628 au experimental values Rg = 3.639 au, a)g=536 cm i, >g g=3.83 cm-i). 

Following the Longuet-Higgins—Salem approach, Buck studied the tendency of aromatic monocyclic compounds to bond alternation with increasing ring size. He used the Huckel model with variable P for the 7T electrons and a Morse potential for the o electrons. His distortion energies show that the o system resists distortion and the tt system favors distortions from D h to D i2)h symmetry in C H annulenes with 77 = 6, 8, 10, 12, 14, 16. The symmetry of the HOMO and LUMO is used to predict whether the C30H30 bond alternation due to the tt electrons should occur. It was subsequently shownthat this method can also be applied to the characterization of antiaromatic polycycles. 

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