Context <p>Fluorinated ferroelectric liquid crystals are promising materials for electro-optical devices, yet the molecular-level response to electric fields remains poorly understood. This DFT/TD-DFT study investigates the fluorinated compound R-C12F2 under static electric fields up to 16.5 V<InlineEquation ID="IEq1"> <EquationSource Format="TEX">$\cdot $</EquationSource> <EquationSource Format="MATHML"><math> <mo>·</mo> </math></EquationSource> </InlineEquation>nm<InlineEquation ID="IEq2"> <EquationSource Format="TEX">$^{-1}$</EquationSource> <EquationSource Format="MATHML"><math> <mmultiscripts> <mrow /> <mrow /> <mrow> <mo>-</mo> <mn>1</mn> </mrow> </mmultiscripts> </math></EquationSource> </InlineEquation>. We report two notable phenomena: a staircase-like evolution of the dipole moment and a field-induced overlap between the HOMO and LUMO orbitals, indicating significant electronic reorganization and discrete molecular reorientations. These findings reveal strong anisotropic field-matter interactions governed by molecular architecture.</p> Methods <p>Geometry optimization and property calculations were performed using Gaussian 16 with the CAM-B3LYP functional and 6-31G(d,p)/6-31<InlineEquation ID="IEq3"> <EquationSource Format="TEX">$^{++}$</EquationSource> <EquationSource Format="MATHML"><math> <mmultiscripts> <mrow /> <mrow /> <mrow> <mo>+</mo> <mo>+</mo> </mrow> </mmultiscripts> </math></EquationSource> </InlineEquation>G(d,p) basis sets. Excited-state properties (UV–Vis, ECD) were computed via TD-DFT, and vibrational spectra (IR, VCD, Raman) were obtained at the same level. Static electric fields (0–16.5 V<InlineEquation ID="IEq4"> <EquationSource Format="TEX">$\cdot $</EquationSource> <EquationSource Format="MATHML"><math> <mo>·</mo> </math></EquationSource> </InlineEquation>nm<InlineEquation ID="IEq5"> <EquationSource Format="TEX">$^{-1}$</EquationSource> <EquationSource Format="MATHML"><math> <mmultiscripts> <mrow /> <mrow /> <mrow> <mo>-</mo> <mn>1</mn> </mrow> </mmultiscripts> </math></EquationSource> </InlineEquation>) were applied along the cartesian axes. An ultrafine integration grid and tight optimization criteria ensured numerical accuracy.</p>

Electric field control of electronic properties in a fluorinated ferroelectric liquid crystal: a DFT/TD-DFT study

期刊论文
发表日期：

2026年7月29日

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Sahbi Essid,
Mohamed Bejaoui,
Hamid Berriche

摘要

Context

Fluorinated ferroelectric liquid crystals are promising materials for electro-optical devices, yet the molecular-level response to electric fields remains poorly understood. This DFT/TD-DFT study investigates the fluorinated compound R-C12F2 under static electric fields up to 16.5 V $\cdot $ $\cdot$ nm $^{-1}$ $^{- 1}$ . We report two notable phenomena: a staircase-like evolution of the dipole moment and a field-induced overlap between the HOMO and LUMO orbitals, indicating significant electronic reorganization and discrete molecular reorientations. These findings reveal strong anisotropic field-matter interactions governed by molecular architecture.

Methods

Geometry optimization and property calculations were performed using Gaussian 16 with the CAM-B3LYP functional and 6-31G(d,p)/6-31 $^{++}$ $^{+ +}$ G(d,p) basis sets. Excited-state properties (UV–Vis, ECD) were computed via TD-DFT, and vibrational spectra (IR, VCD, Raman) were obtained at the same level. Static electric fields (0–16.5 V $\cdot $ $\cdot$ nm $^{-1}$ $^{- 1}$ ) were applied along the cartesian axes. An ultrafine integration grid and tight optimization criteria ensured numerical accuracy.