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  2. Threshold energy - Wikipedia

    en.wikipedia.org/wiki/Threshold_energy

    The threshold energy , to produce three particles of masses , , , i.e. 1 + 2 → a + b + c , {\displaystyle 1+2\to a+b+c,} is then found by assuming that these three particles are at rest in the center of mass frame (symbols with hat indicate quantities in the center of mass frame):

  3. Transition state theory - Wikipedia

    en.wikipedia.org/wiki/Transition_state_theory

    These so-called activation parameters give insight into the nature of a transition state, including energy content and degree of order, compared to the starting materials and has become a standard tool for elucidation of reaction mechanisms in physical organic chemistry. The free energy of activation, ΔG ‡, is defined in transition state ...

  4. Activation energy - Wikipedia

    en.wikipedia.org/wiki/Activation_energy

    In the Arrhenius model of reaction rates, activation energy is the minimum amount of energy that must be available to reactants for a chemical reaction to occur. [1] The activation energy ( E a ) of a reaction is measured in kilojoules per mole (kJ/mol) or kilocalories per mole (kcal/mol). [ 2 ]

  5. Pair production - Wikipedia

    en.wikipedia.org/wiki/Pair_production

    As energy must be conserved, for pair production to occur, the incoming energy of the photon must be above a threshold of at least the total rest mass energy of the two particles created. (As the electron is the lightest, hence, lowest mass/energy, elementary particle, it requires the least energetic photons of all possible pair-production ...

  6. Collision theory - Wikipedia

    en.wikipedia.org/wiki/Collision_theory

    Collision theory is a principle of chemistry used to predict the rates of chemical reactions. It states that when suitable particles of the reactant hit each other with the correct orientation, only a certain amount of collisions result in a perceptible or notable change; these successful changes are called successful collisions.

  7. Activated complex - Wikipedia

    en.wikipedia.org/wiki/Activated_complex

    The activation energy is the minimum amount of energy to initiate a chemical reaction and form the activated complex. [6] The energy serves as a threshold that reactant molecules must surpass to overcome the energy barrier and transition into the activated complex.

  8. Threshold displacement energy - Wikipedia

    en.wikipedia.org/wiki/Threshold_displacement_energy

    In materials science, the threshold displacement energy (T d) is the minimum kinetic energy that an atom in a solid needs to be permanently displaced from its site in the lattice to a defect position. It is also known as "displacement threshold energy" or just "displacement energy".

  9. Energy minimization - Wikipedia

    en.wikipedia.org/wiki/Energy_minimization

    In the field of computational chemistry, energy minimization (also called energy optimization, geometry minimization, or geometry optimization) is the process of finding an arrangement in space of a collection of atoms where, according to some computational model of chemical bonding, the net inter-atomic force on each atom is acceptably close to zero and the position on the potential energy ...