SOJT effect

As a result of the second-order effect, also large C4, 4 2 monocycles are expected to be acetylenic as is explained by the Peierls distortion that is seen in one-dimensional electronic systems with periodic potentials [35b-e]. This effect is associated with the distortion of the potential energy surface to lower the total energy of the system through electron-phonon coupling [35b]. For a molecular system, the same effect is also referred to as the second-order Jahn Teller (SOJT) effect that leads to the vibrational-mode... 

Much more commonly, vibronic interactions involve mixing of two nondegenerate electronic states of different symmetry, under the influence of an appropriate nonsymmetric vibration, which leads to a stabilization of the state of lower energy. This type of vibronic interaction is called a second-order Jahn-Teller (SOJT) effect. SOJT effects occur whenever two electronic states, and Tg, which belong to different irreducible representations, are mixed by a vibration that lowers the molecular symmetry. Therefore, except in diatomics, SOJT effects occur whenever any symmetry element is present in a molecule. 

According to second-order perturbation theory, whether a molecule distorts under the influence of a SOJT effect depends on three factors ... 

Since A g is often small in open-shell molecules, these species are generally much more prone to vibronic interactions than closed-shell systems. Therefore, especially in radical ions, one should never assume that a geometry of high symmetry is the most stable one. The following examples illustrate the operation of SOJT effects in two radical cations. 

SCBD SCP SEM SOJT STM supersonic carbon cluster beam deposition self consistent field scanning electron microscope second-order Jahn-Teller effect scanning tunneling microscopy... 

SOJT second-order Jahn-Teller (effect)... 

SOJT Second-order Jahn-Teller effect. Molecular distortion due to vibronic mixing between two electronic states of different symmetry and energy. 

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