Hydrogen bonds potential energy

The equilibrium condition stated in Eq. (20) and the hydrogen bond potential energy function, Eq, (16), yields ... 

Some information384-386 on the absorption spectra (X-H stretching) of base pairs became available, and it was interesting to test the results of calculations on the hydrogen-bond potential energy surfaces for the base pairs by comparing them with experimentally known quantities. 

Figure 3. Contour diagram of the base stacking potential energy Kg of sequential adenine bases and the hydrogen bonding potential energy VHB of the complementary A T base pairs as a function of the phosphodiester rotation angles

The distribution of bond lengths for a particular two-center bond in the crystal structures of a particular class of biological compounds has a well-defined maximum but is more symmetrical than might be expected from the hydrogen-bond potential energy curve (cf. Figs. 2.4 and 4.2 a, b). 

The hydrogen bonding potential energy is calculated as [Wade, 1993a] ... 

Abbreviations used in table (see also caption to Table 5.2) HB -hydrogen bonding potential energy term self-bb - prediction of side-chain conformation on to template backbone of modeled sequence non-self - prediction of side-chain conformation onto backbone borrowed from a homologous protein structure. 

Hydrogen bonding in water dimer has been extensively studied both theoretically and experimentally. The empirical form for a hydrogen bond potential energy function V b, which is compatible with usual van der Waals functions, is not well established. A clear separation of the coulombic component would... 

Figure 5 HEAH hydrogen-bond potential energy function.

Intermolecular Energies A Critical Test of the (HF)2 Hydrogen Bond Potential Energy Surface... 

TABLE 11. Conformational energies (kcalmol1) of ethylenediamine as calculated ab initio (6-31G ), by the original MM3 force field (MM3) and by MM3 augmented with a directional hydrogen bonding potential function (MM 3-94 Reproduced by permission of John Wiley Sons Ltd... 

Equation (24) can also be used to evaluate h by equating values of A in terms of b at different equilibrium X——Y distances and solving for 6. The hydrogen bond potential function, Eq. (16), may be used to calculate the hydrogen bond energy as all the parameters have been evaluated. The hydrogen bond potential function can also be used to obtain the dependence of potential energy on H—X distance and on the X— Y distance. 

Fig. 8. Schematic representation of the hydrogen-bond potential. The solidline (dipole-dipole interaction potential) and the dot (position of minimum, and energy at the minimum) are the only features that are known. The dashed line is an empirical potential constructed to fit tiho-kfiown data (Poland and Scheraga, 1967).

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