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  2. Mean free path - Wikipedia

    en.wikipedia.org/wiki/Mean_free_path

    In physics, mean free path is the average distance over which a moving particle (such as an atom, a molecule, or a photon) travels before substantially changing its direction or energy (or, in a specific context, other properties), typically as a result of one or more successive collisions with other particles.

  3. Formal charge - Wikipedia

    en.wikipedia.org/wiki/Formal_charge

    Formal charges in ozone and the nitrate anion. In chemistry, a formal charge (F.C. or q*), in the covalent view of chemical bonding, is the hypothetical charge assigned to an atom in a molecule, assuming that electrons in all chemical bonds are shared equally between atoms, regardless of relative electronegativity.

  4. Poisson–Boltzmann equation - Wikipedia

    en.wikipedia.org/wiki/Poisson–Boltzmann_equation

    The linearized Poisson–Boltzmann equation can be used to calculate the electrostatic potential and free energy of highly charged molecules such as tRNA in an ionic solution with different number of bound ions at varying physiological ionic strengths. It is shown that electrostatic potential depends on the charge of the molecule, while the ...

  5. Partial charge - Wikipedia

    en.wikipedia.org/wiki/Partial_charge

    Partial atomic charges are used in molecular mechanics force fields to compute the electrostatic interaction energy using Coulomb's law, even though this leads to substantial failures for anisotropic charge distributions. [1] Partial charges are also often used for a qualitative understanding of the structure and reactivity of molecules.

  6. Charge transfer coefficient - Wikipedia

    en.wikipedia.org/wiki/Charge_transfer_coefficient

    Charge transfer coefficient, and symmetry factor (symbols α and β, respectively) are two related parameters used in description of the kinetics of electrochemical reactions. They appear in the Butler–Volmer equation and related expressions.

  7. Fick's laws of diffusion - Wikipedia

    en.wikipedia.org/wiki/Fick's_laws_of_diffusion

    c 2 − c 1 is the difference in concentration of the gas across the membrane for the direction of flow (from c 1 to c 2). Fick's first law is also important in radiation transfer equations. However, in this context, it becomes inaccurate when the diffusion constant is low and the radiation becomes limited by the speed of light rather than by ...

  8. Molecular mechanics - Wikipedia

    en.wikipedia.org/wiki/Molecular_mechanics

    The most accurate way to solvate a system is to place explicit water molecules in the simulation box with the molecules of interest and treat the water molecules as interacting particles like those in the other molecule(s). A variety of water models exist with increasing levels of complexity, representing water as a simple hard sphere (a united ...

  9. Water model - Wikipedia

    en.wikipedia.org/wiki/Water_model

    where μ is the electric dipole moment of the effectively polarized water molecule (2.35 D for the SPC/E model), μ 0 is the dipole moment of an isolated water molecule (1.85 D from experiment), and α i is an isotropic polarizability constant, with a value of 1.608 × 10 −40 F·m 2. Since the charges in the model are constant, this ...