Building molecular C₁₀-π-cationic interaction systems for reporting quadrupole moments basis

Area of Science:

• Computational Chemistry
• Materials Science
• Nonlinear Optics (NLO)

Background:

• Supramolecular π-cation interactions are explored to enhance nonlinear optical (NLO) properties.
• Molecular C10 systems doped with alkali (Li, Na, K) and alkaline earth metals (Be, Mg, Ca) were investigated.

Purpose of the Study:

• To computationally quantify the effects of metal doping on the quadrupole moments and hyperpolarizabilities (β0) of C10 systems.
• To understand the charge redistribution mechanisms and their impact on NLO properties and reactivity.

Main Methods:

• Density Functional Theory (DFT) calculations using PBE-D3/def2-TZVP level.
• Electronic spectra evaluated via Time-Dependent DFT (TD-DFT).
• Computation of quadrupole moments (Qzz), polarizabilities (α), hyperpolarizabilities (β), transition density matrix (TDM), hole-electron overlap, and charge density difference (CDD).

Main Results:

• Undoped C10 shows high stability with negligible NLO response.
• Na@C10 exhibits the highest hyperpolarizability (β0 = 17,105 a.u.) and quadrupole distortion.
• Mg@C10 displays the lowest energy gap (Eg = 0.19 eV), indicating extreme reactivity, with moderate optical response.
• K@C10 shows minimal enhancement, while Ca@C10 demonstrates a distinct charge redistribution mechanism.

Conclusions:

• Metal doping significantly alters the electronic structure and NLO properties of C10 systems.
• Na and Mg doping show promising potential for developing advanced NLO materials.
• Global reactivity parameters confirm enhanced softness and reduced ionization potentials upon doping.