absolute reaction rate theory a theory that sets out to predict the absolute reaction rate of a chemical reaction from the quantum mechanical description of the potential energy changes during the interaction between chemical species. It is most widely drawn upon in applying thermodynamic reasoning to equilibria between reactants in the ground state and chemical species in the activated state …
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Shapes of s and p orbitals
Shapes of s and p orbitals s orbital can have only one possible orientation (as it’s m quantum is zero), it is spherical in shape i.e., in an s orbital the electron distribution is symmetrical around the nucleus in all directions. However the size of s orbital depends on principal quantum number. Large n means large size. Thus 3s orbital …
Read More »Quantum numbers
Quantum numbers: These are numbers which are used to specify the location and energy of an electron and size, shape and orientation of the orbital to which a particular electron belongs. Principal or total quantum number (n): This quantum number is identical with that used in Bohr Sommer field theory. It can have only non zero positive integral values. i.e. …
Read More »Quantization
Quantization: means that a quantity does not vary continuously. The energy of an electron in an atom cannot have any arbitrary value but only certain characteristic values. A definite quantum of energy is accepted while moving from lower to higher energy level or lost while moving from higher to lower energy level, It does not accept any amount of energy …
Read More »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 …
Read More »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 …
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