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  2. Lanthanide contraction - Wikipedia

    en.wikipedia.org/wiki/Lanthanide_contraction

    The lanthanide contraction is the greater-than-expected decrease in atomic radii and ionic radii of the elements in the lanthanide series, from left to right. It is caused by the poor shielding effect of nuclear charge by the 4f electrons along with the expected periodic trend of increasing electronegativity and nuclear charge on moving from left to right.

  3. Lanthanide - Wikipedia

    en.wikipedia.org/wiki/Lanthanide

    All of the lanthanides form Ln 2 Q 3 (Q= S, Se, Te). [18] The sesquisulfides can be produced by reaction of the elements or (with the exception of Eu 2 S 3) sulfidizing the oxide (Ln 2 O 3) with H 2 S. [18] The sesquisulfides, Ln 2 S 3 generally lose sulfur when heated and can form a range of compositions between Ln 2 S 3 and Ln 3 S 4.

  4. Ionization energy - Wikipedia

    en.wikipedia.org/wiki/Ionization_energy

    The adiabatic ionization energy of a molecule is the minimum amount of energy required to remove an electron from a neutral molecule, i.e. the difference between the energy of the vibrational ground state of the neutral species (v" = 0 level) and that of the positive ion (v' = 0). The specific equilibrium geometry of each species does not ...

  5. Cardiac excitation-contraction coupling - Wikipedia

    en.wikipedia.org/wiki/Cardiac_excitation...

    Cardiac excitation-contraction coupling (Cardiac EC coupling) describes the series of events, from the production of an electrical impulse (action potential) to the contraction of muscles in the heart. [1] This process is of vital importance as it allows for the heart to beat in a controlled manner, without the need for conscious input.

  6. Quantization of the electromagnetic field - Wikipedia

    en.wikipedia.org/wiki/Quantization_of_the...

    The energy content of this volume element at 5 km from the station is 2.1 × 10 −10 × 0.109 = 2.3 × 10 −11 J, which amounts to 3.4 × 10 14 photons per (). Since 3.4 × 10 14 > 1, quantum effects do not play a role. The waves emitted by this station are well-described by the classical limit and quantum mechanics is not needed.

  7. Entropy in thermodynamics and information theory - Wikipedia

    en.wikipedia.org/wiki/Entropy_in_thermodynamics...

    In 1953, Brillouin derived a general equation [10] stating that the changing of an information bit value requires at least kT ln(2) energy. This is the same energy as the work Leo Szilard 's engine produces in the idealistic case, which in turn equals the same quantity found by Landauer .

  8. Goldman equation - Wikipedia

    en.wikipedia.org/wiki/Goldman_equation

    Since the valence has already been accounted for above, the charge q A of each ion in the equation above, therefore, should be interpreted as +1 or -1 depending on the polarity of the ion. There is such a current associated with every type of ion that can cross the membrane; this is because each type of ion would require a distinct membrane ...

  9. Madelung constant - Wikipedia

    en.wikipedia.org/wiki/Madelung_constant

    The electrostatic interaction model of ions in solids has thus been extended to a point multipole concept that also includes higher multipole moments like dipoles, quadrupoles etc. [8] [9] [10] These concepts require the determination of higher order Madelung constants or so-called electrostatic lattice constants.