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The Laporte rule is powerful because it applies to complexes that deviate from idealized O h symmetry. For example, the d-d transitions for [Cr(NH 3) 5 Cl] 2+ are weak (ε < 100) even though the complex is only of C 4v symmetry. [5] The Laporte rule helps explain the intense colors often observed for the tetrahedral complexes.
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 weaker d–d transitions are potentially spin-allowed but always Laporte-forbidden. [2] Charge-transfer bands of transition metal complexes result from shift of charge density between molecular orbitals (MO) that are predominantly metal in character and those that are predominantly ligand in character. If the transfer occurs from the MO ...
These transitions provide substantially longer lasting excited states, since they are Laporte forbidden, thus allowing longer time necessary for the multiple excitations required for upconversion. The concentration of activator ions in UCNPs is also critically important, as this determines the average distance between the activator ions and ...
This "relaxes" the Laporte rule and allows for transitions that would theoretically be forbidden. 24.7.108.102 08:57, 28 February 2007 (UTC) [ reply ] No, 'u' doesn't mean there isn't an inversion centre, in fact there has to be an inversion centre for it to be designated such! g comes from the German gerade which translates as even, and u is ...
Four-time Indianapolis 500 winner Helio Castroneves got a crash course — literally — in stock-car racing at Daytona International Speedway. Castroneves was involved in a seven-car wreck on Lap ...
Instead, the spectrum has a broad peak (spectrum shown below). Based on the T–S diagram, the lowest energy transition is 4 T 1 to 4 T 2, which is seen in the near IR and is not observed in the visible spectrum. The main peak is the energy transition 4 T 1 (F) to 4 T 1 (P), and the slightly higher energy transition (the shoulder) is predicted ...
Otto Laporte (July 23, 1902 – March 28, 1971) was a German-born American physicist who made contributions to quantum mechanics, electromagnetic wave propagation theory, spectroscopy, and fluid dynamics. His name is lent to the Laporte rule in spectroscopy and to the Otto Laporte Award of the American Physical Society. [1]