Erratum: Contribution of covalent bond force to pressure in polymer melts [J. Chem. Phys. 91, 3168 (1989)]

1990 ◽  
Vol 92 (12) ◽  
pp. 7722-7722 ◽  
Author(s):  
J. Gao ◽  
J. H. Weiner
Keyword(s):  
Polymer Melts ◽  
Covalent Bond ◽  
Chem Phys ◽  
Bond Force

Contribution of covalent bond force to pressure in polymer melts

1989 ◽  
Vol 91 (5) ◽  
pp. 3168-3173 ◽  
Author(s):  
J. Gao ◽  
J. H. Weiner
Keyword(s):  
Polymer Melts ◽  
Covalent Bond ◽  
Bond Force

Atomic Forces

2021 ◽  
pp. 93-130
Author(s):  
C. Julian Chen
Keyword(s):  
Perturbation Theory ◽  
Van Der Waals ◽  
Hard Core ◽  
Covalent Bond ◽  
Van Der Waals Force ◽  
Mathematical Form ◽  
Ionic Bond ◽  
Bond Force ◽  
Flat Sample ◽  
Physical Quantities

This chapter discusses the physics and properties of four types of atomic forces occurring in STM and AFM: the van der Waals force, the hard core repulsion, the ionic bond, and the covalent bond. The general mathematical form of the van der Waals force between a tip and a flat sample is derived. The focus of this chapter is the covalent-bond force, which is a key in the understanding of STM and AFM. The concept of covalent bond is illustrated by the hydrogen molecular ion, the prototypical molecule used by Pauling to illustrate Heisenberg’s concept of resonance. The Herring-Landau perturbation theory of the covalent bond, an analytical incarnation of the concept of resonance, is presented in great detail. It is then applied to molecules built from many-electron atoms, to show that the perturbation theory can be applied to practical systems to produce simple analytic results for measurable physical quantities with decent accuracy.

Atomic Forces and Tunneling

2021 ◽  
pp. 131-166
Author(s):  
C. Julian Chen
Keyword(s):  
Landau Theory ◽  
Covalent Bond ◽  
Theoretical Explanation ◽  
Tunneling Conductance ◽  
Explicit Equation ◽  
Bond Force ◽  
Atom Manipulation ◽  
Tunneling Phenomenon ◽  
Metal Tip ◽  
Physical Quantities

This chapter presents a unified theory of tunneling phenomenon and covalent bond force, as a result of the similarity between the Bardeen theory of tunneling and the Herring-Landau theory of the covalent bond. Three general theoretical treatments are presented, which show that tunneling conductance is proportional to the square of the covalent bond interaction energy, or equivalently, the square of covalent bond force. The constant of proportionality is related to the electronic properties of the materials. For the case of a metal tip and a metal sample, an explicit equation contains only measurable physical quantities is derived. Several experimental verifications are presented. The equivalence of covalent bond energy and tunneling conductance provides a theoretical explanation of the threshold resistance observed in atom-manipulation experiments, and points to a method of predicting the threshold resistance for atom manipulation. Theory of imaging wavefunctions with AFM is discussed.

scholarly journals Covalent bond force profile and cleavage in a single polymer chain

2000 ◽  
Vol 113 (6) ◽  
pp. 2497-2503 ◽  
Author(s):  
Lionel Garnier ◽  
Bernard Gauthier-Manuel ◽  
Eric W. van der Vegte ◽  
Jaap Snijders ◽  
Georges Hadziioannou
Keyword(s):  
Polymer Chain ◽  
Covalent Bond ◽  
Bond Force ◽  
Force Profile ◽  
Single Polymer Chain

Aldehyde gold clusters for molecular labeling

1995 ◽  
Vol 53 ◽  
pp. 858-859
Author(s):  
James F. Hainfeld ◽  
Frederic R. Furuya
Keyword(s):  
Covalent Bond ◽  
Aldehyde Group ◽  
Gold Clusters ◽  
Side Reactions ◽  
Amino Groups ◽  
Sodium Cyanoborohydride ◽  
Schiff’S Base ◽  
Protein Molecules ◽  
Hydroxysuccinimide Esters ◽  
Primary Amino

Glutaraldehyde is a useful tissue and molecular fixing reagents. The aldehyde moiety reacts mainly with primary amino groups to form a Schiff's base, which is reversible but reasonably stable at pH 7; a stable covalent bond may be formed by reduction with, e.g., sodium cyanoborohydride (Fig. 1). The bifunctional glutaraldehyde, (CHO-(CH2)3-CHO), successfully stabilizes protein molecules due to generally plentiful amines on their surface; bovine serum albumin has 60; 59 lysines + 1 α-amino. With some enzymes, catalytic activity after fixing is preserved; with respect to antigens, glutaraldehyde treatment can compromise their recognition by antibodies in some cases. Complicating the chemistry somewhat are the reported side reactions, where glutaraldehyde reacts with other amino acid side chains, cysteine, histidine, and tyrosine. It has also been reported that glutaraldehyde can polymerize in aqueous solution. Newer crosslinkers have been found that are more specific for the amino group, such as the N-hydroxysuccinimide esters, and are commonly preferred for forming conjugates. However, most of these linkers hydrolyze in solution, so that the activity is lost over several hours, whereas the aldehyde group is stable in solution, and may have an advantage of overall efficiency.

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