SCHIMBĂRILE STRUCTURALE ÎN MOLECULELE DE TIP AH3 ÎN PROCESELE REDOX INDUSE DE PSEUDOEFECTUL JAHN-TELLER

Iolanta BALAN Institutul de Chimie al AŞM

Abstract

STRUCTURAL CHANGES IN AH3 TYPE MOLECULES IN THE  REDOX PROCESS INDUSED BY PSEUDO JAHN-TELLER EFFECT 

The Pseudo Jahn-Teller Effect (PJTE) is used to rationalize structural changes in the redox processes of NH3 and CH3 molecules by means of analyzing the changes in their symmetry and energy gaps between the ground and lowest excited electronic states that control their PJTE coupling along the distortion coordinates. The numerical values of the vibronic coupling constants were estimated by means of fitting the solutions of the secular equations to the ab initio calculated energy profiles. It is shown that oxidation of NH3 molecule by removing an electron from the high occupied molecular orbital (HOMO) leads to the suppression of the PJTE and to restoration of planar nuclear configuration. Reduction of CH3 molecule enhances the PJTE, leading to its pyramidalization. 

Keywords: pseudo Jahn-Teller effect, redox processes, distortion, vibronic coupling parameters, excited states, ammonia, carbonyl.