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The adiabatic ionization energy of a molecule is the minimum amount of energy required to remove an electron from a neutral molecule, i.e. the difference between the energy of the vibrational ground state of the neutral species (v" = 0 level) and that of the positive ion (v' = 0). The specific equilibrium geometry of each species does not ...
Adiabatic ionization is a form of ionization in which an electron is removed from or added to an atom or molecule in its lowest energy state to form an ion in its lowest energy state. [16] The Townsend discharge is a good example of the creation of positive ions and free electrons due to ion impact.
An adiabatic process (adiabatic from Ancient Greek ἀδιάβατος (adiábatos) 'impassable') is a type of thermodynamic process that occurs without transferring heat between the thermodynamic system and its environment. Unlike an isothermal process, an adiabatic process transfers energy to the surroundings only as work and/or mass flow.
From Koopmans’ theorem the energy of the 1b 1 HOMO corresponds to the ionization energy to form the H 2 O + ion in its ground state (1a 1) 2 (2a 1) 2 (1b 2) 2 (3a 1) 2 (1b 1) 1. The energy of the second-highest MO 3a 1 refers to the ion in the excited state (1a 1) 2 (2a 1) 2 (1b 2) 2 (3a 1) 1 (1b 1) 2, and so on. In this case the order of the ...
The quantum mechanical definition is closer to the thermodynamical concept of a quasistatic process and has no direct relation with adiabatic processes in thermodynamics. In mechanics , an adiabatic change is a slow deformation of the Hamiltonian , where the fractional rate of change of the energy is much slower than the orbital frequency.
Therefore one unitary transformation is performed from the adiabatic representation to the so-called diabatic representation in which the nuclear kinetic energy operator is diagonal. In this representation, the coupling is due to the electronic energy and is a scalar quantity that is significantly easier to estimate numerically.
Temperature is a statistical quantity whose formal definition is = (),, or the change in internal energy with respect to entropy, holding volume and particle number constant. A practical definition comes from the fact that the atoms, molecules, or whatever particles in a system have an average kinetic energy.
When only zero kinetic energy electrons are detected, the photon energy above the adiabatic ionization energy is converted into the internal energy of the photoion AB + The relatively low intensity of the ionizing VUV radiation guarantees one-photon processes, in other words only one, fixed energy photon will be responsible for photoionization.