Dimer separation energies

Electronic Shell Effects in Monomer and Dimer Separation Energies... 

Monomer and dimer separation energies associated with the unimolecular reactions Kyv-i + K, Kyv+ Ka -2 + K2, and Nayv+ Na v-i + Na can be calculated as follows ... 

We note that in the case of dimer separation energies (Figure 4.3) the odd-even alternations cancel out. Parents with closed shells or subshells correspond to maxima, while daughters with closed shells or subshells are associated with minima (e.g. the triplets A = 9-ll,orA = 15-17). 

Figure 4.3 Dimer separation energies, D2,w (see Eq. (43)), from singly cationic K/v clusters in the range 5 < N <27. Solid dots theoretical results derived from the SE-SCM method. Open squares experimental measurements from Ref. [75]. Top panel the spherical model compared to experimental data. Middle panel the spheroidal model compared to experimental data. Lower panel the ellipsoidal model compared to experimental data...

Relativistic DFT calculations have been performed for the noble metal dimers Cu2 and Au2 as well as for the transition metal compounds Fe2 and FeO. Separation energies, equihbrium separations, and the oscillator frequency are compared non-relativistic versus relativistic, all electron versus pseudo-potential and LDA versus GGA results. 

Now let us consider tire implications of tliese results for energy transfer. First we recognize tliat tliere is no directed energy transfer of tire fonn considered in the incoherent case. Molecules in tire dimer cannot be recognized as well defined separate entities tliat can capture and translate excitation from one to anotlier. The captured excitation belongs to tire dimer, in otlier words, it is shared by botli molecules. The only counteriDart to energy migration... 

Figure 4-4. Schematic rcprcsenlalion of ihc one-clcclron structure of a single siilbcnc molecule and that of a cofacial dimer formed by iwo chains separated by 4 A. lire INDO-ealculated energy splil ot the HOMO and LUMO levels when going from Ihc isolated molecule to the dimer are also given.

Figure 4-11. INDQ/SCI-caleulalcd evolution of the transition energies (upper pan) and related intensities (bottom pan) of the lowest two optical transitions of a cofacial dimer formed by two stilbenc molecules separated by 4 A as a function of the dihedral angle between the long molecular axes, when rotating one molecule around the stacking axis and keeping the molecular planes parallel (case IV of Figure 4-10). Open squares (dosed circles) correspond to the S(J - S2 (S0 — S, > transition.

Table 2. Singlet-triplet energy separations (AEsx) in M-H monomers, M—M bond dissociation energies (BDEs), SCF calculated bond lengths for the hypothetical, linear dimers HMMH (M = B, Al, Ga, In, or Tl) ...

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