Pseudo Jahn-Teller effect in SeX2 (X=F,Cl,Br,I) molecules: A theoretical investigation
Subject Areas :
Keywords: Pseudo-Jan-Teller effect, Symmetry breaking, The Natural Bonding Orbital, The stability energy.,
Abstract :
If the excited and ground electronic modes are mixed, the symmetry breaking in the high symmetrical configuration of a molecule is expected. It has been shown that high-symmetry forms of any molecule undergo structural distortions due to the pseudo-Jahn-Teller Effect (PJTE). the linear (D∞h) and bent form (C2v) geometries of selenium difluoride (1), selenium dichloride (2), selenium dibromide (3) and selenium diiodide (4) have been optimized at the B3LYP levels with Def2-TZVPP the basis set on every atom. Furthermore, studies have explored the associations between the PJT stabilization energies, hardness, and structural parameters, corrected electronic energies, electronegativity and hardness. The natural bond orbital (NBO)interpretation is associated with [Lp(3)X →σ*(1)S-X] to obtain stabilization energy E(2) ,vibronic coupling constant(Fij). The energy gaps between the reference states (Δ)in the bent (C2v) structures decrease from 1 to 4 compounds. The plot of EPJT is linearly correlated with Δ [η(C2V)-η(D∞h)] of compounds 1–4. The calculated Δ[η(C2V)-η(D∞h)] parameter increases from 1 to 4 compounds. It was shown that the linear (D∞h) is more unstable than the bent (C2v) configuration, due to the strong lone pair–lone pair repulsion. PJT stabilization energy increases from compounds 1 to 4, which represent greater stability of 1 to 4 compounds.