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The Jahn–Teller effect (JT effect or JTE) is an important mechanism of spontaneous symmetry breaking in molecular and solid-state systems which has far-reaching consequences in different fields, and is responsible for a variety of phenomena in spectroscopy, stereochemistry, crystal chemistry, molecular and solid-state physics, and materials science.
Second-order Jahn-Teller distortion provides a rigorous and first-principles approach to the distortion problem. The interactions between the HOMOs and LUMOs to afford a new set of molecular orbitals is an example of second-order Jahn-Teller distortion.
The pseudo Jahn–Teller effect (PJTE), occasionally also known as second-order JTE, is a direct extension of the Jahn–Teller effect (JTE) where spontaneous symmetry breaking in polyatomic systems (molecules and solids) occurs even when the relevant electronic states are not degenerate. The PJTE can occur under the influence of sufficiently ...
The term can also refer to octahedral influenced by the Jahn–Teller effect, which is a common phenomenon encountered in coordination chemistry. This reduces the symmetry of the molecule from O h to D 4h and is known as a tetragonal distortion.
Six-coordinate complexes of the Cu(II) ion, with the generic formula [CuL 6] 2+, are subject to the Jahn-Teller effect so that the symmetry is reduced from octahedral (point group O h) to tetragonal (point group D 4h). Since d orbitals are centrosymmetric the related atomic term symbols can be classified in the subgroup D 4.
The prominent shoulder in this absorption band is due to a Jahn–Teller distortion which removes the degeneracy of the two 2 E g states. However, since these two transitions overlap in a UV-vis spectrum, this transition from 2 T 2g to 2 E g does not require a Tanabe–Sugano diagram.
The cubic perovskite structure is distorted into an orthorhombic structure by a strong Jahn–Teller distortion of the oxygen octahedra. [2] LaMnO 3 often has lanthanum vacancies as evidenced by neutron scattering. For this reason, this material is usually referred as LaMnO 3+ẟ.
The compound is the prototypical antiaromatic hydrocarbon with 4 pi electrons (or π electrons). It is the smallest [n]-annulene ([4]-annulene).Its rectangular structure is the result of a pseudo [3] - (or second order) Jahn–Teller effect, which distorts the molecule and lowers its symmetry, converting the triplet to a singlet ground state. [4]