Electrostatically collapsed

Molecules with polar atoms or charged groups can form intramolecular interactions such as internal H-bonds or cation-rr interactions. As a consequence energy minimization in vacuo often results in electrostatically collapsed conformations due to the dominance of these intramolecular interactions. Several compounds in... 

Shui, X. Q., Sines, C. C., McFailisom, L., VanderVeer, D., and Williams, L. D. (1998). Structure of the potassium form of CGCGAATTCGCG-DNA deformation by electrostatic collapse around inorganic cations. Biochem. 37, 16877-87. 

Electrostatic effects have long been recognized in commercial HPLC columns for SEC of proteins (15,21,22). The usual remedy is to add 100 mM salt to the mobile phase. This works here too the Lys and Asp peaks collapse into the Gly peak with 100 mM salt (Eig. 8.8). High concentrations of sodium sulfate were added to determine the role played in SEC by hydrophobic interactions (sodium sulfate, a structure-forming salt, strengthens such interactions). Sodium sulfate increased the retention only of the most hydrophobic amino acids to any extent, and then only when the concentration approached 1 M. Clearly, hydrophobic interaction cannot account for the elution order of amino acids on PolyHEA. 

It has been proposed that a combination of various molecular forces is responsible for the phenomenon of condensation [38]. Probably, electrostatic forces play the most important role in the screening of phosphate repulsion by counterions, thus helping in the collapse of... 

In a second hypothesis, one can consider that the adsorption is mainly due to hydrogen bonds and that electrostatic attraction between polymer and particles only brings them together. In such case, the influence of c and r on the stability should be related to the number of amide groups available for hydrogen bounds and the increase of salinity should lead to the collapse of the chain and reduce the probability of interparticles bridging. 

Just as the first term in the Schroedinger equation describes the kinetic energy of an electron system, and the second term deals with the potential energy, so are these the two parts of any simple model. Electrostatic forces provide attraction between the atoms, while kinetic energy keeps the system from collapsing by exerting a quantum mechanical Schroedinger pressure. ... 

The dipole-dipole electrostatic interaction and a repulsiveterm that avoids collapsing of dipoles was expressed as ... 

In the ionic model, the energy of an inorganic solid is assumed to be the sum of all the potentials, C/y, between atoms i and j. These consists of two terms, a classical electrostatic potential, C/y,eiectrostatio determined by the charges on the atoms, and a quantum mechanical term, C/,y,Fermi> that includes the repulsion that prevents individual atoms from collapsing into each other as well as any residual contributions from covalent bonding (eqn (2.1)) ... 

The experimental trends in bonding and structure which we have discussed in the previous chapter cannot be understood within a classical framework. None of the elements and only very few of the thousand or more binary AB compounds are ionic in the sense that the electrostatic Madelung energy controls their bonding. And even for ionic systems, it is a quantum mechanical concept that stops the lattice from collapsing under the resultant attractive electrostatic forces the strong repulsion that arises as the ion cores start to overlap is direct evidence that Pauli s exclusion principle is alive and well and hard at work ... 

In our first paper [34] in this field, we presented a theory which described the effect of electrostatic interactions of charges on the chain on the collapse. 

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