Homonuclear curve

Recently, numerous studies reported the application of homonuclear and heteronuclear selective recoupling schemes on uniformly labelled ligand interacting with membrane receptors. The polarization exchange curves were fitted with the two-spin model and showed that it is possible to determine intemuclear distances up to 4.5 A.118... 

The first-row homonuclear diatomic molecules A2 of main-group elements (A = B, C, N, O, F) exhibit a well-known diversity of ground-state multiplicities, bond lengths, and bond energies. Calculated potential-energy curves for low-lying singlet and triplet states of these species are pictured in Fig. 3.27 and summarized in Table 3.13 (with comparison experimental values). Because these homonuclear... 

Figure 3.27 Singlet (solid line) and (if lower) triplet (dotted line) potential-energy curves for first-row homonuclear diatomics B (circles), C (squares), N (triangles),...

Let us also briefly examine the corresponding behavior in second- and third-row homonuclear diatomics. Figures 3.31(a) and (b) display the calculated potential-energy curves for these species (ground-state multiplicities only) and Table 3.16 summarizes the equilibrium bond lengths and bond energies. 

Fig. 3.3 The electron density of the homonuclear molecule (upper panel) can be regarded as the sum of the non-interacting or frozen free-atom electron densities (lower panel) and the quantum mechanically induced bond density (middle panel). The dashed curve represents the first-order approximation, eqn (3.26), for the bond density, the deviation from the exact result (full curve) being due to the sizeable value of the overlap integral namely S = 0.59 at / = 2au.

Figure 5.4 Homonuclear diatomic energy curve in dimensionless units...

The plot of observed d vs ) for homonuclear diatomics, shown in Figure 5.6(b), follows the theoretical covalence curve within experimental uncertainty. 

The predicted course of reaction between a heteronuclear pair of atoms is shown in Figure 7.2. Promotion is once more modeled with isotropic compression of both types of atom. The more electropositive atom (at the lower quantum potential) reaches its valence state first and valence density starts to migrate from the parent core and transfers to an atom of the second kind, still below its valence state. The partially charged atom is more readily compressible to its promotion state, as shown by the dotted line. When this modified atom of the second kind reaches its valence state two-way delocalization occurs and an electron-pair bond is established as before. It is notable how the effective activation barrier is lowered with respect to both homonuclear (2Vq)i barriers to reaction. The effective reaction profile is the sum of the two promotion curves of atoms 1 and 2, with charge transfer. 

Figure 3.16 Potential curves for the lscr and 2pa states of HD+. In the homonuclear (H2+), the two states are asymptotically degenerate the degeneracy is lifted in the he nuclear case by 29.8 cm-1 (inset). (Taken from Fig. 1, Ref. [83].)...

Figure 1.14 Typical potential energy curves for a homonuclear rare gas systems illustrating the non-bound state, the first excited 3 + and states, and the 2S+ ionic states [410], The bound states all have potential minima at an internuclear separation R0.

Experimental studies have shown that, in practice, the effect of second-order quadrupolar interactions can produce gross deviations from a Gaussian-type decay curve, reflecting the influence of higher moments on the time evolution behavior [ 11 ]. It has been shown, however, that dipolar information can still be obtained if the analysis is restricted to the initial curvature in the limit of short dipolar evolution times (2ti<200 ps). The validity of this approach has been tested recently for homonuclear Na- Na dipole-dipole interactions in crystalline solids, for which the M2 values are readily calculable from the known crystal structures [11]. 

Curves for the negative-ion states of H2 and L are chosen to illustrate the procedures for the homonuclear diatomic molecules. Curves for benzene and naphthalene are examples of excited states for larger molecular negative ions. These illustrate the relationship between gas phase acidities and thermal electron attachment reactions. Such correlation procedures can be applied to systematic predictions for many different problems. 

The homonuclear diatomic molecules are the simplest closed set of molecules. Many of the electron affinities of the main group diatomic molecules have been measured by anion photoelectron spectroscopy (PES), but only a few have been confirmed. These Ea can be examined by their systematic variation in the Periodic Table. Calculating Morse potential energy curves for the anions and comparing them with curves for isoelectronic species confirm experimental values. The homo-nuclear diatomic anions of Group IA, IB, VI, VII, and 3d elements and NO are examined first. 

Figure 9.9 ECD data for homonuclear diatomic molecules plotted as In KT312 versus 1,000/7. The curves drawn through the data are calculated using the parameters given in Table 9.3.

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