quantum chemical study of the jahn – teller effect on the distortions of xo 2 (x = o, s, se, te) systems

Preliminary researches provided essentialinformation about the optimizedconfiguration of triatomic xo2 (x = o, s,se, te) systems, which were bent in theground state and linear in their first excitedstate. the jahn-teller effects including thejahn-teller (jte), the renner-teller effect(rte), and the pseudo jahn–teller effect(pjte) are parts of the most importantreasons for structural distortion in thehigh–symmetry configurations for eachmolecular system. this study purpose wasto investigate the dependence between pjtparameters including the vibronic couplingconstant values (f), energy gap betweenreference states (δ), and initial forceconstant (k0). in all above mentionedmolecules stability were increased with thereduction in the symmetry level. thisincrement was attributed to the pjte. thevibronic coupling interaction between theground (σg), and the first excited states(πu) through the pjte problem (pjt (σg+πu) × πu) was because of the asymmetryand molecules bending phenomenon. thehardness difference parameter δ[η (c2v) -η(d∞h)] decreases from o to te (30.42,22.66, 22.65, 22.58 kcal/mol). thesechanges could explain the trend, whichwere observed for the d∞h c2vconversion process.