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  2. Antibonding molecular orbital - Wikipedia

    en.wikipedia.org/wiki/Antibonding_molecular_orbital

    H 2 1sσ* antibonding molecular orbital. In theoretical chemistry, an antibonding orbital is a type of molecular orbital that weakens the chemical bond between two atoms and helps to raise the energy of the molecule relative to the separated atoms. Such an orbital has one or more nodes in the bonding region between the nuclei.

  3. Pi bond - Wikipedia

    en.wikipedia.org/wiki/Pi_bond

    Most orbital overlaps that do not include the s-orbital, or have different internuclear axes (for example p x + p y overlap, which does not apply to an s-orbital) are generally all pi bonds. Pi bonds are more diffuse bonds than the sigma bonds. Electrons in pi bonds are sometimes referred to as pi electrons. Molecular fragments joined by a pi ...

  4. List of equations in quantum mechanics - Wikipedia

    en.wikipedia.org/wiki/List_of_equations_in...

    One particle: N particles: One dimension ^ = ^ + = + ^ = = ^ + (,,) = = + (,,) where the position of particle n is x n. = + = = +. (,) = /.There is a further restriction — the solution must not grow at infinity, so that it has either a finite L 2-norm (if it is a bound state) or a slowly diverging norm (if it is part of a continuum): [1] ‖ ‖ = | |.

  5. Sigma-pi and equivalent-orbital models - Wikipedia

    en.wikipedia.org/wiki/Sigma-pi_and_equivalent...

    For the hydrogen fluoride molecule, for example, two F lone pairs are essentially unhybridized p orbitals of π symmetry, while the other is an sp x hydrid orbital of σ symmetry. An analogous consideration applies to water (one O lone pair is in a pure p orbital, another is in an sp x hybrid orbital).

  6. Pi-stacking - Wikipedia

    en.wikipedia.org/wiki/Pi-stacking

    As a result, pi–pi and cation–pi interactions are important factors in rational drug design. [24] One example is the FDA-approved acetylcholinesterase (AChE) inhibitor tacrine which is used in the treatment of Alzheimer's disease. Tacrine is proposed to have a pi stacking interaction with the indolic ring of Trp84, and this interaction has ...

  7. Hückel method - Wikipedia

    en.wikipedia.org/wiki/Hückel_method

    The variational theorem guarantees that the lowest value of that gives rise to a nontrivial (that is, not all zero) solution vector (,, …,) represents the best LCAO approximation of the energy of the most stable π orbital; higher values of with nontrivial solution vectors represent reasonable estimates of the energies of the remaining π ...

  8. Dewar–Chatt–Duncanson model - Wikipedia

    en.wikipedia.org/wiki/Dewar–Chatt–Duncanson...

    On the left, a filled pi-orbital on C 2 H 4 overlaps with an empty d-orbital on the metal. On the right, an empty pi-antibonding orbital on C 2 H 4 overlaps with a filled d-orbital on the metal The Dewar–Chatt–Duncanson model is a model in organometallic chemistry that explains the chemical bonding in transition metal alkene complexes .

  9. Molecular orbital - Wikipedia

    en.wikipedia.org/wiki/Molecular_orbital

    Complete acetylene (H–C≡C–H) molecular orbital set. The left column shows MO's which are occupied in the ground state, with the lowest-energy orbital at the top. The white and grey line visible in some MO's is the molecular axis passing through the nuclei. The orbital wave functions are positive in the red regions and negative in the blue.