Some important phenomena in the atomic world 

Zeeman effect, Paschen-Back effect & Stark effect

    We see that, the electron configuration in an atom is determined by three factors. a) Attractive force from the nucleus, b) repulsive forces between electrons c) buoyant force by space matter. When an atom is placed in a strong electric or magnetic field, its electron configuration is altered from the atom’s normal state. That is, some of the electrons in the electron shells are shifted to inner or outer transitory shells by the influence of the external field.

    When such an atom is excited, it will emit radiations with the natural frequencies of the ‘newly created electron shells’ and other transitory shells. The Zeeman Effect is the direct indication of strength of the magnetic field. I.e. when a weak field affects only outer electrons, a stronger field influences both the inner and outer electrons. Also, lighter elements can demonstrate Zeeman Effect in a weak field comparatively than heavy elements, because of the electrons in a lighter atom are loosely binded than that of a heavy atom.

Absorption spectrum

     Every shell (electron shells and transitory shells) of an atom has its own unique natural frequency (or resonant frequency). When a cooled gas is placed in the path of continues spectrum of light, dark absorption lines will be appeared in the resulting spectrum. This absorption lines are caused by the absorption of that particular frequencies by the gas atoms. That means the natural frequencies of some of the electron shells and primary transitory shells of the gas atoms are same as the frequencies of the absorbed spectrum lines.

 Emission spectrum

    If the same gas is examined at an oblique angle, bright emission lines will be visible against a dark background. The emission spectrum lines are caused by the reflection of light (that absorbed by the gas atoms) by the electrons in the above stated shells. That is, the emission lines are purely the reflection of light from the gas atoms by its electrons. If we can make the whole of the absorption spectrum lines or emission spectrum lines of an atom in all frequencies from Infrared rays to X-rays at their cooled state (non-excited state), we can directly observe the natural frequencies of each of the electron shells and the primary transitory shells of that atom. The total number of electron shells and the primary transitory shells in an atom are equal to the total number of absorption or emission spectrum lines. And the natural frequencies of the electron shells and primary transitory shells are, if we consider the emission lines, then the highest frequency line for the innermost electron shell and the lowest frequency line for the outermost primary transitory shell. Same as, if we consider the absorption lines, then the highest frequency absorption line for the innermost electron shell and the lowest frequency absorption line for the outermost primary transitory shell.

Band spectra

    Band spectra are produced when the emitting substance is in the molecular state; therefore they are also called molecular spectra. When atoms are bonded together to form a molecule, the natural frequencies of the overlapped space matter shells are altered from their original natural frequencies. So, a molecule of a substance emits its own unique band spectra when it is excited and we can identify a molecule by analyzing its band spectra. 

Mechanism of reflection (reflection of light)

    The binding energy of 'light reflecting electrons' to its atoms / molecules or to the surface of a light reflecting material will be equal to or greater than that of the energy of incident photons. When light falls on these electrons, they will oscillate with the frequency of the incident photons and the light will be reflected.

Photoelectric effect

    In an external photoelectric effect, electrons are liberated from the surface of a metallic conductor by absorbing energy from light shining on the metal’s surface. In this case, the binding energy of photoelectrons (electrons that are liberated) to the metal surface will be always lower than the energy of the incident photons that causes the photoelectric effect. The kinetic energy of a photoelectron is depends on the energy (frequency) of the incident photon. When energetic photons fall on the low binding energy electrons in the metal surface, they will oscillate with the frequency of incident photons. This oscillation causes, the oscillating electrons induce its oscillations to the elastic-outer shells of nearby atoms that in the metal surface. This oscillations of outer shells of the atoms cause, it to expel (kick) the low binding energy electrons from their surface. The kinetic energy of a photoelectron increases with the increasing of the frequency of incident photon. That is, as the ejection of photoelectrons are purely because of the elasticity of outer shells of atoms, as the energy of incident photons increases, the atoms kick the electrons with more kinetic energy.

Thermionic emission

    We see that atoms are highly elastic and vibrations and elastic collisions between atoms cause the temperature of a material. As the thermal vibration of atoms in a material increases, its atoms kick out the low binding energy electrons the material. This is the reason for the Thermionic emission.

 Compton Effect

    Compton Effect occurs when a high-energy photon falls on an atomic electron, which with having a binding energy lowers than the energy of incident photon. We see that, every electron shell in an atom has its own unique natural frequency. When a high frequency photon falls on an electron that in an electron shell which with having a natural frequency less than that of the frequency of incident photon, because of an atomic electron can only oscillate in the natural frequency of its electron shell within that shell, the electron will oscillate in the natural frequency of its shell, and a photon with the natural frequency of that electron shell is emitted at an angle to the direction of the path of the incident photon. This emission of the photon, which has a long wavelength than the incident photon, is the Compton photon. We see that, when an electron is excited, it will jump from an inner region to an outer region in the atom. So, the Compton electron will jump at an angle to the direction of the path of the incident photon.

Pair production

    The pair production is one of the most interesting demonstrations for the presence of space matter in atoms. When a gamma ray photon with the energy of 1.2 MeV is passed through near a heavy nucleus (that is, through the innermost transitory shells) it can result the production of one electron and one positron. The quantity of space matter that closer to a heavy nucleus is equal to or more than the mass of one electron and one positron, because of its high density at these region. When such an energetic gamma ray photon is passed through the high-density space matter region, the individual space matter units will be bonded together to produce the electron-positron pair. When a pair production occurs, the equal amount of space matter (with the mass of one electron and one positron) will be entered from outside of the atom and the natural densities of the space matter in the atomic shells will be always maintained.

Primakoff effect

    Primakoff effect (the resonant production of neutral mesons by high-energy photons interacting with an atomic nucleus) is also an evidence for the space matter in atoms.