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One of the guiding principles in modern chemical dynamics and spectroscopy is that the motion of the nuclei in a molecule is slow compared to that of its electrons. This is justified by the large disparity between the mass of an electron and the typical mass of a nucleus and leads to the Born-Oppenheimer approximation and the idea that the structure and dynamics of a chemical species are largely determined by nuclear motion on potential energy surfaces.The potential energy surfaces are obtained within the adiabatic or Born–Oppenheimer approximation. This corresponds to a representation of the molecular wave function where the variables corresponding to the molecular geometry and the electronic degrees of freedom are separated. The non separable terms are due to the nuclear kinetic energy t

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  • Diabatische Zustandsänderung (de)
  • Diabatic (en)
  • Diabático (pt)
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  • One of the guiding principles in modern chemical dynamics and spectroscopy is that the motion of the nuclei in a molecule is slow compared to that of its electrons. This is justified by the large disparity between the mass of an electron and the typical mass of a nucleus and leads to the Born-Oppenheimer approximation and the idea that the structure and dynamics of a chemical species are largely determined by nuclear motion on potential energy surfaces.The potential energy surfaces are obtained within the adiabatic or Born–Oppenheimer approximation. This corresponds to a representation of the molecular wave function where the variables corresponding to the molecular geometry and the electronic degrees of freedom are separated. The non separable terms are due to the nuclear kinetic energy t (en)
  • Um processo diabático é aquele em que ocorre a transferência de calor, ou seja, é oposto de um processo adiabático. Em química quântica, a superfície de energia potencial é obtida através de um ou da aproximação de Born-Oppenheimer. Isso corresponde a uma representação da função de onda molecular, onde as variáveis ​​correspondentes a geometria molecular e graus de liberdade eletrônicos são tratados separadamente. Os termos não separáveis são devidos aos termos de energia cinética nuclear no hamiltoniano molecular e são chamados superfície de energia potencial acopladas. Na vizinhança de um cruzamento evitado ou de uma intersecção cónica, esses termos não pode ser negligenciados. (pt)
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  • One of the guiding principles in modern chemical dynamics and spectroscopy is that the motion of the nuclei in a molecule is slow compared to that of its electrons. This is justified by the large disparity between the mass of an electron and the typical mass of a nucleus and leads to the Born-Oppenheimer approximation and the idea that the structure and dynamics of a chemical species are largely determined by nuclear motion on potential energy surfaces.The potential energy surfaces are obtained within the adiabatic or Born–Oppenheimer approximation. This corresponds to a representation of the molecular wave function where the variables corresponding to the molecular geometry and the electronic degrees of freedom are separated. The non separable terms are due to the nuclear kinetic energy terms in the molecular Hamiltonian and are said to couple the potential energy surfaces. In the neighbourhood of an avoided crossing or conical intersection, these terms cannot be neglected. One therefore usually performs one unitary transformation 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. In the diabatic representation, the potential energy surfaces are smoother, so that low order Taylor series expansions of the surface capture much of the complexity of the original system. However strictly diabatic states do not exist in the general case. Hence, diabatic potentials generated from transforming multiple electronic energy surfaces together are generally not exact. These can be called pseudo-diabatic potentials, but generally the term is not used unless it is necessary to highlight this subtlety. Hence, pseudo-diabatic potentials are synonymous with diabatic potentials. (en)
  • Um processo diabático é aquele em que ocorre a transferência de calor, ou seja, é oposto de um processo adiabático. Em química quântica, a superfície de energia potencial é obtida através de um ou da aproximação de Born-Oppenheimer. Isso corresponde a uma representação da função de onda molecular, onde as variáveis ​​correspondentes a geometria molecular e graus de liberdade eletrônicos são tratados separadamente. Os termos não separáveis são devidos aos termos de energia cinética nuclear no hamiltoniano molecular e são chamados superfície de energia potencial acopladas. Na vizinhança de um cruzamento evitado ou de uma intersecção cónica, esses termos não pode ser negligenciados. Aquele geralmente executa uma transformação unitária de uma representação , chamado de representação diabática, em que o operador de energia cinética nuclear é uma matriz diagonal. Nesta representação, o acoplamento é devido ao e é uma quantidade escalar que é significativamente mais fácil para ser estimado numericamente. Na representação diabática, as superfícies de energia potencial são mais suaves que as expansões de baixa ordem da série de Taylor da superfície, capturando grande parte da complexidade do sistema original. Infelizmente, os estados estritamente diabáticos não existem no caso geral. Portanto, os potenciais diabáticos são gerados pela transformação conjunta de múltiplas superfícies de energia electrônicas, em geral não são exatas. Estes podem ser chamados de potenciais pseudo-diabático, mas geralmente o termo não é usado a menos que seja necessário destacar esta sutileza, deste modo potenciais pseudo-diabáticos e potenciais diabáticos são sinônimos. (pt)
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