Hall Effect

— of the transverse electric field $\vec{E}$ a conductor or a semiconductor with a current density $\vec{j}$ while placing it in a magnetic field with induction $\vec{B}$. For isotropic conductor $\vec{E}=R[\vec{B} \vec{j}]$, where $R$ —Hall constant, which depends on the nature of the conductor. Opened in 1880, Amer. scientists EG Hall (1855-1938).

Chlorine (Cl)

— a chemical element, atomic number $17$, atomic mass $35.453$. Yellow-green gas with a pungent odor, density $3.214\ \mathrm{kg} / \mathrm{m}^{3}$, boiling point: $−33.6\ ^{\circ} \! {\mathrm{C}}$, melting point: $−100.98\ ^{\circ} \! {\mathrm{C}}$.

Chemical Potential

— state function that is used to describe a thermodynamic system with a variable number of particles. For $i$-ies component homogeneous system the molar Ch. p. equal $$ \mu_{i}=\left(\frac{\partial \Phi}{\partial n_{i}}\right)_{p, T . n_{k}} $$ where $\Phi$ — thermodynamic Gibbs potential, $P$ — pressure, $T$ — absolute temperature, $n_{i}$ — the number of moles $i$-ies components, $n_{k}$ — the number of moles of all other system components. Molar Ch. p. measured in joules per mole (J/mol).

Chemical Bonding

— the interaction of atoms, which is accompanied by restructuring their electron shells leads to the formation of polyatomic structures (molecules, crystals) with socialized electron shell. Ch.b. quantum mechanical nature has in two limiting cases is a covalent bond and ionic bond.

Chemical Element

— the kind of atoms that have the same nuclear charge and therefore the same number of electrons in atomic shells. The main characteristics Ch.e. is the atomic number and atomic mass, the relationship Ch. e. displays the periodic system of elements of Mendeleev.

Wave Vector

— vector $\vec{k}$, the direction of which coincides with the direction of propagation of the traveling wave, and the numerical value is the wave number $k=\dfrac{2 \pi}{\lambda}$.

Wave Number

  1. The value associated with the wavelength ratio $k=\dfrac{2 \pi}{\lambda}$.
  2. Spectroscopy — the reciprocal of the wavelength, ie $\nu=\dfrac{1 }{\lambda}=\dfrac{k}{2 \pi}$.

Wave Equation

— differential equations with partial derivatives describing the propagation of waves (disturbance) in a certain environment. In the case of small oscillations and homogeneous medium. W. e. for plane wave has the form $$ \frac{\partial^{2} u}{d x^{2}}+\frac{\partial^{2} u}{d y^{2}}+\frac{\partial^{2} u}{d z^{2}}=\frac{1}{v^{2}} \frac{\partial^{2} u}{d t^{2}} $$ where $u=u(x, y, z, t)$ — rejection of the physical quantity from the equilibrium position at coordinates $x, y, z$, $v$ — speed of wave propagation in the medium; $t$ — time.

Wave Function

— a function of the coordinates and time $\psi(x, y, z, t)$, that describes microparticles (electrons, protons, etc.). system or microparticles (atoms, molecules, atomic nuclei, crystal), taking into account their wave properties (see. De broglie waves). W. f. is the solution of the Schrödinger equation, is subject to regulation and can be both real and complex. Square module W. f.