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The Laporte rule is a rule that explains the intensities of absorption spectra for chemical species. It is a selection rule that rigorously applies to atoms, and to molecules that are centrosymmetric, i.e. with an inversion centre. It states that electronic transitions that conserve parity are forbidden. Thus transitions between two states that ...
The Laporte rule is a selection rule formally stated as follows: In a centrosymmetric environment, transitions between like atomic orbitals such as s-s, p-p, d-d, or f-f, transitions are forbidden. The Laporte rule (law) applies to electric dipole transitions, so the operator has u symmetry (meaning ungerade, odd).
The dissociation of nitrous oxide is a well-studied process: [1]. N 2 O → N 2 + O. O atoms have a triplet ground state. Methoxy cation has a triplet ground state. In a mass spectrometer, it dissociates into singlet products (formyl cation and H 2):
The lattice must also be stable under chemical and photochemical conditions, as these are the environments the conversion will take place within. Finally, this host lattice ought to have low symmetry, allowing for a slight relaxation of the Laporte selection rules. The normally forbidden transitions lead to an increase in the f-f intermixing ...
Near room temperature, these salts are yellow , but these solids become blue when heated to near 70 °C. The bright blue color is characteristic of tetrahedral [NiCl 4] 2−, the intensity being a consequence of the Laporte selection rule. The yellow color results from a polymer consisting of octahedral Ni centers.
A fast-spreading wildfire that erupted this week northwest of Los Angeles roared from nothing to nearly 10,000 acres − in a matter of hours.
The state Republican Party on Thursday voted to keep a winner-take-all threshold likely to benefit Trump.
The remaining two integrals contributing to the probability amplitude determine the electronic spatial and spin selection rules. The Franck–Condon principle is a statement on allowed vibrational transitions between two different electronic states; other quantum mechanical selection rules may lower the probability of a transition or prohibit ...