جميع المواضيع المتعلقة بـ ‘quantum’

 

adiabatic approximation

adiabatic approximation An ap­proximation used in quantum me­chanics when the time dependence of parameters, such as the internuclear distance between atoms in a molecule, is slowly varying. This ap­proximation means that the solution of the Schrodinger equation at one time goes continuously over to the solution at a later time. It was formu­lated by Max Born and the Soviet physicist Vladimir Alexandrovich Fock (1898-1974) in 1928. The “Born-Oppenheimer…

كلمات دليلية: , , , , ,

ab-initio calculation

A method of calculating atomic and molecular structure directly from the first principles of quantum mechanics, without using quantities derived from experiment (such as ionization energies found by spectroscopy) as parameters.

Ab-initio calculations require a large amount of numerical computation; the amount of computing time required increases rapidly as the size of the atom or molecule increases. The development of computing power has enabled the properties of both small…

كلمات دليلية: , , , , , ,

Energy levels and sub-levels

Not all the electrons in an atom are located the same distance from the nucleus. Electrons reside in regions of space called shells, or principal energy levels, which are identified with numbers called principal quantum numbers. The number of electrons that can exist in each energy level is limited.

The maximum number of electrons for a specific energy is equal to 2n2, where n is the number of the…

كلمات دليلية: , , , , , , , , , , ,