The ground-state intermolecular potential energy surface for the fluorobenzene-argon van der Waals complex is evaluated using the coupled-cluster singles and doubles including connected triple excitations model, with the augmented correlation consistent polarized valence double-zeta basis set extended with a set of 3s3p2d1f1g midbond functions. In the surface minima the Ar atom is located above and below the fluorobenzene plane at a distance of 3.562 A from the fluorobenzene center of mass and at an angle of 6.33 degrees with respect to the axis perpendicular to the fluorobenzene plane. The corresponding binding energy is 391.1 cm(-1). Both these results and the eigenvalues obtained from the potential compare well with the experimental data available.
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http://dx.doi.org/10.1063/1.1695553 | DOI Listing |
Chem Sci
January 2025
Department of Materials Engineering Science, Graduate School of Engineering Science, Osaka University Toyonaka Osaka 560-8531 Japan
In this study, we theoretically examined the mechanism of aromaticity induced in closely stacked cofacial π-dimers of 4π antiaromatic molecules, which is called stacked-ring aromaticity, in terms of the effective number of π-electrons ( ) and Baird's rule. High-precision quantum chemical calculations combined with a multi-configurational wavefunction analysis revealed that double-triplet [(TT)] and intermolecular charge-transfer (CT) electron configurations mix substantially in the ground state wavefunctions of cyclobutadiene and Ni(ii) norcorrole dimer models at small stacking distance (). Since the T configuration gives rise to two unpaired electrons, the remaining 4 - 2 π electrons still participate in the intramolecular conjugation, which can be interpreted as the origin of the aromaticity of each monomer.
View Article and Find Full Text PDFMolecules
November 2024
Institute of Physics, University of Rzeszów, 35-310 Rzeszów, Poland.
The main purpose of this study is to characterize the nature of the low-energy singlet excited states of the anthranilic acid homodimer (AA) and their changes (symmetry breaking) caused by deformation of the centrosymmetric, ground state structure of AA towards the geometry of the S state. We employ both the correlated ab initio methods (approximate Coupled Clusters Singles and Doubles-CC2 and CASSCF/NEVPT2) as well as the DFT/TDDFT calculations with two exchange-correlation functionals, i.e.
View Article and Find Full Text PDFPhys Chem Chem Phys
November 2024
Institute of Advanced Materials, Wroclaw University of Science and Technology, Faculty of Chemistry, Wybrzeże Wyspiańskiego 27, 50-370 Wrocław, Poland.
In this work, several plausible intra- and intermolecular photoinduced processes of the Watson-Crick base pairs of adenine with uracil (A-U) or thymine (A-T) according to the results of spin component scaling variant of algebraic diagrammatic construction up to the second order [SCS-ADC(2)] calculations are discussed. Although widely explored, these systems lack complete characterization of possible intramolecular relaxation channels perturbed by intermolecular interactions. In particular, we address the still open debate on photodeactivation purine-ring puckering at the C2 or C6-atom position of adenine.
View Article and Find Full Text PDFJ Am Chem Soc
November 2024
Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138, United States.
Despite the utility of copper catalysts for the insertion of carbene moieties into C-H bonds, the copper carbene intermediate often invoked in these transformations has not been isolated. Herein, we describe the synthesis and structural characterization of a series of copper benzylidenes utilizing the sterically encumbered dipyrrin ligand (L)H. These isolated copper carbenes demonstrate intramolecular insertion into the primary C(sp)-H bond of the ligand (L)H and intermolecular insertion into ethereal and allylic C-H bonds.
View Article and Find Full Text PDFPhys Rev Lett
October 2024
Department of Physics, University of Nevada, Reno, Nevada 89557, USA.
By leveraging the hyperfine interaction between the rotational and nuclear spin degrees of freedom, we demonstrate extensive magnetic control over the electric dipole moments, electric dipolar interactions, and ac Stark shifts of ground-state alkali-dimer molecules such as KRb(X^{1}Σ^{+}). The control is enabled by narrow avoided crossings and the highly ergodic character of molecular eigenstates at low magnetic fields, offering a general and robust way of continuously tuning the intermolecular electric dipolar interaction for applications in quantum simulation, quantum sensing, and dipolar spinor physics.
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