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  2. Linear molecular geometry - Wikipedia

    en.wikipedia.org/wiki/Linear_molecular_geometry

    Neutral AX 2 molecules with linear geometry include beryllium fluoride (F−Be−F) with two single bonds, [1] carbon dioxide (O=C=O) with two double bonds, hydrogen cyanide (H−C≡N) with one single and one triple bond. The most important linear molecule with more than three atoms is acetylene (H−C≡C−H), in which each of its carbon ...

  3. Walsh diagram - Wikipedia

    en.wikipedia.org/wiki/Walsh_diagram

    For the simplest AH 2 molecular system, Walsh produced the first angular correlation diagram by plotting the ab initio orbital energy curves for the canonical molecular orbitals while changing the bond angle from 90° to 180°. As the bond angle is distorted, the energy for each of the orbitals can be followed along the lines, allowing a quick ...

  4. Molecular geometry - Wikipedia

    en.wikipedia.org/wiki/Molecular_geometry

    Linear: In a linear model, atoms are connected in a straight line. The bond angles are set at 180°. For example, carbon dioxide and nitric oxide have a linear molecular shape. Trigonal planar: Molecules with the trigonal planar shape are somewhat triangular and in one plane (flat). Consequently, the bond angles are set at 120°.

  5. Equilibrium unfolding - Wikipedia

    en.wikipedia.org/wiki/Equilibrium_unfolding

    A number of models have been proposed to explain this observation prominent among them being the denaturant binding model, solvent-exchange model (both by John Schellman [4]) and the Linear Extrapolation Model (LEM; by Nick Pace [5]). All of the models assume that only two thermodynamic states are populated/de-populated upon denaturation.

  6. Chemical graph generator - Wikipedia

    en.wikipedia.org/wiki/Chemical_graph_generator

    Two substructures of a caffeine molecule are given, (A) and (B). The overlap of these substructures is highlighted in green in the caffeine structure (C). Molecular structure generation is a branch of graph generation problems. [1] Molecular structures are graphs with chemical constraints such as valences, bond multiplicity and fragments. These ...

  7. Hückel method - Wikipedia

    en.wikipedia.org/wiki/Hückel_method

    The Hückel method or Hückel molecular orbital theory, proposed by Erich Hückel in 1930, is a simple method for calculating molecular orbitals as linear combinations of atomic orbitals. The theory predicts the molecular orbitals for π-electrons in π-delocalized molecules , such as ethylene , benzene , butadiene , and pyridine .

  8. Molecular orbital diagram - Wikipedia

    en.wikipedia.org/wiki/Molecular_orbital_diagram

    For a diatomic molecule, an MO diagram effectively shows the energetics of the bond between the two atoms, whose AO unbonded energies are shown on the sides. For simple polyatomic molecules with a "central atom" such as methane (CH 4) or carbon dioxide (CO 2), a MO diagram may show one of the identical bonds to the central atom. For other ...

  9. Energy minimization - Wikipedia

    en.wikipedia.org/wiki/Energy_minimization

    As described above, some method such as quantum mechanics can be used to calculate the energy, E(r) , the gradient of the PES, that is, the derivative of the energy with respect to the position of the atoms, ∂E/∂r and the second derivative matrix of the system, ∂∂E/∂r i ∂r j, also known as the Hessian matrix, which describes the curvature of the PES at r.