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  2. Woodward's rules - Wikipedia

    en.wikipedia.org/wiki/Woodward's_rules

    Woodward's rules, named after Robert Burns Woodward and also known as Woodward–Fieser rules (for Louis Fieser) are several sets of empirically derived rules which attempt to predict the wavelength of the absorption maximum (λ max) in an ultraviolet–visible spectrum of a given compound.

  3. Bragg's law - Wikipedia

    en.wikipedia.org/wiki/Bragg's_law

    The glancing angle θ (see figure on the right, and note that this differs from the convention in Snell's law where θ is measured from the surface normal), the wavelength λ, and the "grating constant" d of the crystal are connected by the relation: [11]: 1026 = ⁡ where is the diffraction order (= is first order, = is second order, [10]: 221 ...

  4. List of unsolved problems in chemistry - Wikipedia

    en.wikipedia.org/wiki/List_of_unsolved_problems...

    Protein folding problem: Is it possible to predict the secondary, tertiary and quaternary structure of a polypeptide sequence based solely on the sequence and environmental information? Inverse protein-folding problem: Is it possible to design a polypeptide sequence which will adopt a given structure under certain environmental conditions?

  5. Matter wave - Wikipedia

    en.wikipedia.org/wiki/Matter_wave

    The de Broglie wavelength is the wavelength, λ, associated with a particle with momentum p through the Planck constant, h: =. Wave-like behavior of matter has been experimentally demonstrated, first for electrons in 1927 and for other elementary particles , neutral atoms and molecules in the years since.

  6. Rydberg formula - Wikipedia

    en.wikipedia.org/wiki/Rydberg_formula

    In 1890, Rydberg proposed on a formula describing the relation between the wavelengths in spectral lines of alkali metals. [2]: v1:376 He noticed that lines came in series and he found that he could simplify his calculations using the wavenumber (the number of waves occupying the unit length, equal to 1/λ, the inverse of the wavelength) as his unit of measurement.

  7. Gas electron diffraction - Wikipedia

    en.wikipedia.org/wiki/Gas_electron_diffraction

    Gas electron diffraction (GED) is one of the applications of electron diffraction techniques. [1] The target of this method is the determination of the structure of gaseous molecules, i.e., the geometrical arrangement of the atoms from which a molecule is built up.

  8. Rydberg–Ritz combination principle - Wikipedia

    en.wikipedia.org/wiki/Rydberg–Ritz_combination...

    The combination principle is explained using quantum theory. Light consists of photons whose energy E is proportional to the frequency ν and wavenumber of the light: E = hν = hc/λ (where h is the Planck constant, c is the speed of light, and λ is the wavelength. A combination of frequencies or wavenumbers is then equivalent to a combination ...

  9. Molecular vibration - Wikipedia

    en.wikipedia.org/wiki/Molecular_vibration

    A molecular vibration is a periodic motion of the atoms of a molecule relative to each other, such that the center of mass of the molecule remains unchanged. The typical vibrational frequencies range from less than 10 13 Hz to approximately 10 14 Hz, corresponding to wavenumbers of approximately 300 to 3000 cm −1 and wavelengths of approximately 30 to 3 μm.