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  2. Chemical bond - Wikipedia

    en.wikipedia.org/wiki/Chemical_bond

    Examples of Lewis dot diagrams used to represent electrons in the chemical bonds between atoms, here showing carbon (C), hydrogen (H), and oxygen (O). Lewis diagrams were developed in 1916 by Gilbert N. Lewis to describe chemical bonding and are still widely used today. Each line segment or pair of dots represents a pair of electrons.

  3. J-coupling - Wikipedia

    en.wikipedia.org/wiki/J-coupling

    Example 1 H NMR spectrum (1-dimensional) of ethanol plotted as signal intensity vs. chemical shift.There are three different types of H atoms in ethanol regarding NMR. The hydrogen (H) on the −OH group is not coupling with the other H atoms and appears as a singlet, but the CH 3 − and the −CH 2 − hydrogens are coupling with each other, resulting in a triplet and quartet respectively.

  4. Bond graph - Wikipedia

    en.wikipedia.org/wiki/Bond_graph

    For example, for the bond of an electrical system, the flow is the current, while the effort is the voltage. By multiplying current and voltage in this example you can get the instantaneous power of the bond. A bond has two other features described briefly here, and discussed in more detail below. One is the "half-arrow" sign convention.

  5. Compliance constants - Wikipedia

    en.wikipedia.org/wiki/Compliance_constants

    Besides chemical bonds, compliance constants are also useful for determining non-covalent bonds, such as H-bonds in Watson-Crick base pairs. [17] Grunenberg calculated the compliance constant for each of the donor-H⋯acceptor linkages in AT and CG base pairs and found that the central N-H⋯N bond in CG base pair is the strongest one with the ...

  6. Modern valence bond theory - Wikipedia

    en.wikipedia.org/wiki/Modern_valence_bond_theory

    The total wave function is optimized using the variational method by varying the coefficients of the basis functions in the valence bond orbitals and the coefficients of the different spin functions. In other cases only a sub-set of all possible spin functions is used. Many valence bond methods use several sets of the valence bond orbitals.

  7. Molecular dynamics - Wikipedia

    en.wikipedia.org/wiki/Molecular_dynamics

    The method is applied mostly in chemical physics, materials science, and biophysics. Because molecular systems typically consist of a vast number of particles, it is impossible to determine the properties of such complex systems analytically; MD simulation circumvents this problem by using numerical methods.

  8. Cross section (physics) - Wikipedia

    en.wikipedia.org/wiki/Cross_section_(physics)

    In physics, the cross section is a measure of the probability that a specific process will take place in a collision of two particles. For example, the Rutherford cross-section is a measure of probability that an alpha particle will be deflected by a given angle during an interaction with an atomic nucleus .

  9. Random phase approximation - Wikipedia

    en.wikipedia.org/wiki/Random_phase_approximation

    Bubble diagrams, which result in the RPA when summed up. Solid lines stand for interacting or non-interacting Green's functions, dashed lines for two-particle interactions. The random phase approximation (RPA) is an approximation method in condensed matter physics and nuclear physics.