In this work, two distinct regulation strategies—atomic doping modification and oriented external electric field (OEEF) modulation—are adopted to achieve systematic and continuous tuning of the electronic and optical properties of lithium-doped boron clusters. First, using the Crystal Structure Analysis by Particle Swarm Optimization (CALYPSO) structural prediction algorithm combined with density functional theory (DFT), the geometric structures, electronic properties, and optical properties are systematically investigated for Li-doped B8− clusters. Structural searches reveal that the introduction of Li atoms can completely reconstruct the planar B8− framework into a three-dimensional structure with the Li atom located at the periphery of the boron ring. Based on the global minimum structures, we calculate the average binding energy, dissociation energy, second-order energy difference, and HOMO–LUMO gap. Calculated results indicate that the umbrella-shaped LiB8− cluster with C7v point group symmetry exhibits relatively high stability. Subsequently, charge transfer behavior is analyzed, and the photoelectron, infrared, and Raman spectra are simulated using the Multiwfn program. Second, with the global minimum structure of LiB8− cluster as the research prototype, OEEFs with different directions and intensities are applied to systematically explore the variations in structural parameters, dipole moment, energy levels, charge distribution, as well as IR and Raman spectra, without altering the original geometric configuration. Results demonstrate that OEEFs enable effective and continuous regulation of multiple electronic and optical properties. This work provides new insights into dual mode property tuning and offers theoretical guidance for the design of boron-based functional nanomaterials.
Reconciling high energy performance, low sensitivity, and high thermal stability remains a central challenge in the molecular design of energetic materials, as enhanced energy output is often accompanied by increased sensitivity and reduced thermal stability. Here, we systematically elucidate the microscopic mechanism by which the spatial position of nitro groups relative to ring N-oxide oxygen governs initial decomposition pathways of furoxan-based energetic materials. Using density functional theory (DFT) combined with transition-state theory, we comparatively investigated two typical zero-oxygen-balanced structural analogues: 3,3′-dinitro-4,4′-azo-furoxan (DNAFO) and 4,4′-dinitro-3,3′-dioxide-furoxan (DNDFO). The calculated Gibbs free energy barriers reveal a distinct mechanistic bifurcation: in the ortho configuration, decomposition is predominantly initiated by C–NO2 homolysis through a low Gibbs free energy difference of 9.2 kcal mol−1, whereas in the non-ortho configuration, cleavage of the ring N–O bond adjacent to the ring N-oxide oxygen is favored, with a barrier of 20.3 kcal mol−1. Electrostatic potential (ESP), atomic dipole moment corrected Hirshfeld (ADCH) charge, and Mayer bond order analyses indicate that this pathway switching originates from substituent-induced charge redistribution, which selectively modulates the strength and reactivity of specific chemical bonds. For non-ortho configured systems, the bridging architecture exerts a relatively limited influence on the intrinsic rate-determining N–O cleavage barrier, suggesting that bridging motifs can instead be optimized with consideration of oxygen balance and crystal density. The established “position-electronics-reactivity” relationship provides microscopic insight into the structure-dependent initial decomposition of furoxan derivatives and offers a theoretical basis for the rational design of energetic materials that balance energy release capability with enhanced thermal stability.
Transition metal-anchored nitrogen-doped graphene single-atom catalysts (SACs) have emerged as promising catalysts that combine the advantages of both homogeneous and heterogeneous catalysis. Two common vacancy motifs in nitrogen-doped graphene-based SACs are the pyridinic and pyrrolic vacancy sites. Despite their importance for catalyst design, quantitative insights into the intrinsic differences in their metal–support bonding interactions and their impact on the preferred metal binding site are still lacking. Here, we have quantum chemically investigated the trends in bonding interactions between Period 4 transition metals (TM = Ti, V, Cr, Mn, Fe Co, Ni, Cu, and Zn) and these vacancy motifs using relativistic, dispersion-corrected periodic density functional theory in combination with the activation strain model and Kohn-Sham molecular orbital (KS-MO) analyses. Regardless of the vacancy motif, the metal–support interaction follows the same trend across Period 4, namely a strengthening from Ti to Ni followed by a weakening from Ni to Zn. This trend originates from the interplay between the increasing effective nuclear charge and the gradual filling of the metal's 3d atomic orbitals. Additionally, the vacancy motif plays a key role in determining the preferred transition metal binding site. Ti and V preferentially bind to the larger pyrrolic vacancy site because the planar coordination minimizes Pauli repulsion between the TM and the support. In contrast, Cr through Zn favor the pyridinic motif, where shorter TMN bonds and a larger CNC angle enhance both electrostatic and orbital interactions. Together, these insights could aid in the rational design of future SACs.
The effect of Dunkl deformation parameters on the energy eigenvalues of the Deng-Fan potential is evaluated in this study. The conformable fractional Nikiforov-Uvarov method is employed to obtain the eigensolutions by solving the nonrelativistic Dunkl Schrödinger equation. The Pekeris approximation scheme is used to check the centrifugal barrier term. In addition, the energy solutions of Deng-Fan potential are obtained in the Minkowski space-time and without the Dunkl deformation parameter, as special cases. Energy eigenvalues for the selected diatomic molecules are seen to be significantly influenced by the Dunkl deformation parameter, fractional parameter, kinetic pre-factor and quantum state values considered. Our numerical results are also supported with graphical illustrations, which are discussed extensively.
This study conducts theoretical simulations to explore the synergistic regulation of chalcogen-substituent electronegativity and solvent polarity on the excited-state proton transfer (ESPT) behavior of three BPDI derivatives (BPDI-O, BPDI-S, BPDI-Se) and clarify the microscopic mechanisms of their excited-state double proton transfer (ESDPT). Geometric parameter statistics and infrared spectral analysis were performed to investigate the variations of hydrogen bond lengths, bond angles, and O-H stretching vibrational frequencies in different substituted systems. The results verify prominent hydrogen bond strengthening in the S1 state for all derivatives, where substituent electronegativity differences induce distinct excited-state hydrogen bond intensities. Quantum theory of atoms in molecules (QTAIM) topological analysis of bond critical point (BCP) electron density, topological parameters, and hydrogen bond energies confirms that chalcogen electronegativity precisely regulates hydrogen bonding interactions in BPDI systems. Frontier molecular orbitals (FMOs) results show that chalcogen substitution rearranges molecular charge distribution, produces favorable excited-state charge recombination properties, providing suitable electronic structures for ESPT. Potential energy surfaces (PESs) were constructed to elucidate the stepwise ESPT pathways and behavioral differences of the three derivatives. Comparative analysis reveals that solvent polarity effectively modulates excited-state hydrogen bond strength and reaction barriers. Nonpolar solvents notably lower the energy barrier of the first proton transfer step (I → II) and greatly promote ESPT reactions. This work clarifies the dual regulatory mechanism of intrinsic atomic electronegativity and extrinsic solvent polarity effects of BPDI derivatives, offering reliable theoretical guidance for molecular design, performance optimization, and optoelectronic applications of novel BPDI functional materials.
A detailed study of the influence of the cylindrical harmonic confining potential on the properties of the hydrogen molecule in its ground state is carried out, for the range of angular frequencies of the potential up to 10 a.u. Highly accurate electronic wavefunctions are obtained with the variational method, in the basis of explicitly correlated Gaussian functions. In comparison to the free molecule, the chemical bond of the confined molecule becomes shorter and stronger. Neither the bond length nor the dissociation energy under the strongest considered confinement are influenced considerably by the relativistic effects, although the values of the relativistic energy corrections are large.
Localized orbital locator (LOL), which is a function derived from the kinetic energy density, is known to provide detailed features of the electronic structure of molecules in a way close to chemist's viewpoint, that is, by examining and quantifying interatomic connections. In this study we show that the extension of this function to electronic excited states gives an opportunity to explore modifications of the electronic structure caused by electronic excitations. In particular, changes of bond character, number and type of lone pairs, and emergence of long-range features can be detected by the application of LOL to excited-state and ground-state densities. A good agreement between the conclusions from the LOL study and the hole-particle natural transition orbitals (NTO) representation has been found, but the LOL description can be made quantitative and more detailed, if needed. Test calculations supporting these findings have been performed for selected small cases (ethene, tetrafluoroethene, and their dimer) and for the real-life examples of benzaldehyde and 4-pyridin-1-ium-1-ylphenolate.
Transition-metal single-atom catalysts anchored on two-dimensional nanostructures provide an effective strategy for tuning electronic properties and gas-monitoring behavior. In this work, density functional theory calculations are performed to investigate a tri-unit hexagonal boron nitride framework with an anthracene-like configuration (Tri-hBNA) and its single-atom-decorated derivatives (Ag, Au, Cu Co, Fe, Ni, Pt, and Zn). Structural and binding-energy analyses confirm the high thermodynamic stability of pristine and metal-decorated systems, with metals preferentially anchored at the central region without inducing structural distortion. Metal decoration significantly modulates the wide bandgap of Tri-hBNA by introducing metal-derived states and, for magnetic dopants, spin polarization. Gas-monitoring performance toward methanol and formaldehyde is evaluated via adsorption energies, recovery times, electronic structure, and charge-transfer analyses. Pristine Tri-hBNA shows weak physisorption, whereas metal decoration markedly enhances adsorption. Coinage metals favor reversible detection, while Co, Cu, and Ni induce strong chemisorption, indicating potential for gas capture or activation.
This study investigated the potential of a Be-decorated C12B8 nanocage as a selective and sensitive platform for hazardous gas sensing. Structural optimization identified the C–C bridge as the most favorable binding site for the Be atom, featuring a high binding energy of −3.02 eV. Subsequent adsorption studies involving CH2, NO2, NO, NH3, and H2Se revealed prominent electronic perturbations, as evidenced by high adsorption energy and substantial charge transfer, which collectively indicated strong adsorbate–substrate interactions. Weaker interactions with CH4, CO, and SO2 emphasized the selective adsorption capability of the nanocage. First-principles computations revealed a reduction in hardness and energy gap after the adsorption for reactive gases and confirmed ionic and intermediate bonding characteristics. Additionally, reduced density gradient and density of states analyses validated substantial charge transfer and electronic coupling for reactive gases. These findings establish Be-decorated C12B8 nanocages as efficient and selective sensors, demonstrating their promising applications in environmental monitoring and industrial safety.
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