Hydrogen bond geometric definition

Hydrogen-Bond Geometric Definition The hydrogen bond is intact if the distance R between two molecules is shorter than a value... 

The three-dimensional conformation of a protein is called its tertiary structure. An a-helix can be either twisted, folded, or folded and twisted into a definite geometric pattern. These structures are stabilized by dispersion forces, hydrogen bonding, and other intermo-lecular forces. 

Table 2. Symbols for Topological Indexes, Geometrical Parameters, and Hydrogen Bonding Parameter and Their Definitions...

Surprisingly, this is stiil debated. A geometrical definition is easier than a chemical one. The hydrogen bond X-H. -A is constituted with a donor X-H and an acceptor A. Readers will note that this convention is exactly the opposite as that used in the rest of the chemical literature, wherein donors are electron-rich species, and acceptors are electron deficient. The hydrogen bond may be described in terms of the d, D, 6. and r as shown in Fig. 1. and certain limits and ranges are well accepted for... 

H-Bonds. Hydrogen bonding analyses of the protein and ligand complexes use a geometric hydrogen bond definition adopted in terms of the proton donor and lone pair acceptor positions. This information is useful to estimate the number of favorable hydrogen bonds for each inhibitor. 

The sharp first peak and following deep minimum of gon(A ) for normal liquid water (at 1.8 A and 2.4 A, respectively) become much less pronounced under supercritical conditions (Fig. 7b). These two characteristic features of gon( ) observed in computer simulations, as well as experimentally (Soper et. al. 1997), are the basis of a simple geometric definition of a hydrogen bond, whereby the bond is assumed to exist between any pair of H2O molecules whose respective O and H atoms are separated by less than i HB = 2.4 A. Integration under gon(A ) up to the chosen threshold distance provides a convenient way to quantitatively estimate the average number of H-bonds in which an individual molecule participates under various thermodynamic conditions (e.g.,... 

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