Using a deformed exponential function and the molecular-orbital theory for the simplest molecular ion, two new analytical functions are proposed to represent the potential energy of ground-state diatomic systems. The quality of these new forms was tested by fitting the ab initio electronic energies of the system LiH, LiNa, NaH, RbH, KH, H2, Li2, K2, H 2 (+) , BeH(+) and Li 2 (+) . From these fits, it was verified that these new proposals are able to adequately describe homonuclear, heteronuclear and cationic diatomic systems with good accuracy. Vibrational spectroscopic constant results obtained from these two proposals are in good agreement with experimental data.
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http://dx.doi.org/10.1007/s00894-014-2297-2 | DOI Listing |
J Comput Chem
January 2025
Institute of Chemistry, Saint Petersburg State University, St. Petersburg, Russia.
In the framework of SMD approach a systematic computational study of structural, electronic and thermodynamic properties of molecular complexes of Cl, ICl and I with series of N-containing Lewis bases in solvents of different polarity was carried out. Results indicate that molecular complexes of Cl with strong and medium-strong LB undergo spontaneous ionization in the acetonitrile solution. The increase of the solvent polarity can change the nature of interaction in X'XLB systems from molecular X'X ← LB donor-acceptor complexes to 3-center 4-electron bound X'→X ← LB in solvents of medium polarity and to the contact ion pairs X'→[XLB] in polar solvents.
View Article and Find Full Text PDFProc Natl Acad Sci U S A
December 2024
Department of Chemistry, University of Hawai'i at Manoa, Honolulu, HI 96822.
The cyclopentadiene (CH) molecule has emerged as a molecular building block of nonplanar polycyclic aromatic hydrocarbons (PAHs) and carbonaceous nanostructures such as corannulene (CH), nanobowls (CH), and fullerenes (C) in deep space. However, the underlying elementary gas-phase processes synthesizing cyclopentadiene from acyclic hydrocarbon precursors have remained elusive. Here, by merging crossed molecular beam experiments with rate coefficient calculations and comprehensive astrochemical modeling, we afford persuasive testimony on an unconventional low-temperature cyclization pathway to cyclopentadiene from acyclic precursors through the reaction of the simplest diatomic organic radical-methylidyne (CH)-with 1,3-butadiene (CH) representing main route to cyclopentadiene observed in TaurusMolecular Cloud.
View Article and Find Full Text PDFJ Mol Model
December 2024
Department of Theoretical Chemistry, Faculty of Chemistry, Jagiellonian University, Gronostajowa 2, 30-387, Krakow, Poland.
Context: The interpretation of ETS-NOCV for typical covalent and dative-covalent chemical bonds is presented and compared with that for halogen bonds. Possible tuning of the strength of halogen bonding is considered, first by applying an electric field (modeled by the point charges or the electric field vector), and then by constructing a model transition-metal complex with enhanced strength of halogen bonding. For all the systems, the ETS-NOCV picture is supplemented by the analysis of the deformation in molecular electrostatic potential (ΔMEP).
View Article and Find Full Text PDFMolecules
November 2024
Department of Chemistry, Biochemistry and Physics, Marist College, 3399 North Road, Poughkeepsie, NY 12601, USA.
Valence bond theory (VB) was used to determine the extent and driving forces for covalent vs. dative bonding in 10-valence-electron diatomic molecules N, CO, NO, CN, P, SiS, PS, and SiP. VBSCF calculations were performed at the CCSD(T)/cc-pVDZ optimized geometries.
View Article and Find Full Text PDFMaterials (Basel)
November 2024
Institute of Molecular Physics, Polish Academy of Sciences, M. Smoluchowskiego 17, 60-179 Poznań, Poland.
To obtain materials or metamaterials with desired elastic properties that are tailor-made for a particular application, it is necessary to design a new material or composite (which may be cumbersome) or to modify the structure of existing materials in order to change their properties in the desired direction. The latter approach, although also not easy, seems favourable with respect to parameters like costs and time-to-market. Despite the fact that elastic properties are one of the oldest studied physical parameters of matter, our understanding of the processes at the microstructural level, that are behind these properties, is still far from being complete.
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