TY - JOUR ID - 105457 TI - Quantum chemical study of the Jahn – Teller effect on the distortions of XO2 (X = O, S, Se, Te) systems JO - Eurasian Chemical Communications JA - ECC LA - en SN - 2717-0535 AU - Esmaeili, Ali AU - Fazaeli, Reza AU - Mohammadi Nasab, Esmat AD - Department of Chemistry, Arak Branch, Islamic Azad University, Arak, Iran AD - Department of Chemistry, South Tehran Branch, Islamic Azad University, Tehran, Iran Y1 - 2020 PY - 2020 VL - 2 IS - 7 SP - 739 EP - 749 KW - the Jahn-Teller effect KW - vibronic interactions KW - Ab initio KW - Quantum KW - symmetry breaking DO - 10.33945/SAMI/ECC.2020.7.1 N2 - Preliminary researches provided essential information about the optimized configuration of triatomic XO2 (X = O, S, Se, Te) systems, which were bent in the ground state and linear in their first excited state. The Jahn-Teller effects including the Jahn-Teller (JTE), the Renner-Teller effect (RTE), and the pseudo Jahn–Teller effect (PJTE) are parts of the most important reasons for structural distortion in the high symmetry configurations for each molecular system. This study purpose was to investigate the dependence between PJT parameters including the vibronic coupling constant values ​​(F), energy gap between reference states (Δ), and initial force constant (K0). In all above mentioned molecules, stability were increased with the reduction in the symmetry level. This increment was attributed to the PJTE. The vibronic coupling interaction between the ground (Σg), and the first excited states (Πu) through the PJTE problem (PJT (Σg+ Πu) × Πu) was because of the asymmetry and molecules bending phenomenon. The hardness difference parameter Δ[η (C2V) -η (D∞h)] decreases from O to Te (30.42, 22.66, 22.65, 22.58 Kcal/mol). These changes could explain the trend, which were observed for the D∞h  → C2V conversion process. UR - https://www.echemcom.com/article_105457.html L1 - https://www.echemcom.com/article_105457_f6f5e5d2a4f281a4bb58493e59b4cf08.pdf ER -