Recent progress in solar technology has drawn attention to novel inorganic cubic perovskites like Sr ₃ SbCl ₃ , due to their excellent physical properties and solar cell potential, as supported by machine learning (ML) insights.

The growing demand for sustainable energy and the environmental drawbacks of lead-based perovskites have led to the emergence of lead-free double perovskites as promising alternatives. In this work, first-principles calculations based on density functional theory (DFT) are employed to systematically investigate the structural, mechanical, electronic, optical, and thermodynamic properties of fluoride-based double perovskites A₂InAgF₆ (A = Na, K, and Rb). Structural analysis confirms that all three compounds are stable in the cubic space group, with negative formation energies. Mechanical evaluations demonstrate that all three compounds satisfy the Born-stability criteria and exhibit ductile behavior. Electronic band structure calculations reveal that these materials are direct bandgap semiconductors, with bandgaps increasing from 3.02 eV for Na₂InAgF₆ to 3.88 eV for Rb₂InAgF₆ using the Hybrid-HSE06 functional. Furthermore, the materials exhibit low reflectivity and strong optical absorption in the UV range, alongside stable thermodynamic profiles at high temperature. These findings highlight the potential of A₂InAgF₆ compounds for next-generation optoelectronic, photovoltaic, and thermoelectric applications.

We report a computational study of the potential energy surface (PES) and vibrational bound states for the ground electronic state of ${Li}_2^{+}Kr$. The PES was calculated in Jacobi coordinates at the Restricted Coupled Cluster method RCCSD(T) level of calculation and using aug-cc-pVnZ (n = 4 and 5) basis sets. Afterward, this PES is extrapolated to the complete basis set (CBS) limit for correction. The obtained interaction energies were, then, interpolated numerically using the reproducing kernel Hilbert space polynomial (RKHS) approach to produce analytic expressions for the 2D-PES. The analytical PES is used to solve the nuclear Schrodinger equation to determine the bound states’ eigenvalues of ${Li}_2^{+}Kr$ for a $J$= 0 total angular momentum configuration and to understand the effects of orientational anisotropy of the forces and the interplay between the repulsive and attractive interaction within the potential surface. In addition, the radial and angular distributions of some selected bound state levels, which lie below, around, and above the T-shaped 90° barrier well, are calculated and discussed. We note that the radial distributions clearly acquire a more complicated nodal structure and correspond to bending and stretching vibrational motions “mode” of the $Kr$ atom along the radial coordinate, and the situation becomes very different at the highest bound states levels with energies higher than the T-shaped 90° barrier well. The shape of the distributions becomes even more complicated, with extended angular distributions and prominent differences between even and odd states.

The present study aims to generate the potential energy curves (PECs) and spectroscopic constants for barium alkaline earth (AE) atoms interacting with rare gas (RG) atoms (He, Ne, Ar, Kr, and Xe). The study focuses on investigating the van der Waals bonds that characterize the interactions between alkaline-earth metals and RG atoms, with a specific emphasis on employing the Tang and Toennies (TT) potential model, known to accurately describe such interactions. The TT potential model was employed in conjunction with combining rules to calculate its parameters, which include dispersion coefficients C _2n and Born-Mayer constants A and b. Additionally, we have conducted high-level ab initio calculations at the CCSD(T) level for all Ba-RG ground states. Obtained PECs from both methods have been used to evaluate the spectroscopic properties D _e, R _e, ω_e, B _e, and ω_eχ_e. Our findings reveal that the derived spectroscopic constants from the TT model exhibit good agreement with the results obtained from CCSD(T) calculations and with other available theoretical studies. Furthermore, to gain insights into the relative differences among AE-RG species, we calculated the κ parameter for AE-RG and AE⁺-RG (AE = Sr, Ca, Mg, Ba; RG = He-Xe) complexes. It is found that except for the case of Ba-RG and Ba⁺-RG, the κ values within the same series, AE-RG and AE⁺-RG, are remarkably close to each other.