Centres de bandes et constantes d'anharmonicité de la molécule du trifluorure de phosphore PF3

In this paper, we establish interesting relationships linking rovibrational band-centers and anharmonic constants of symmetric top molecule. Using these relationships, nine accurate values of the xij and gij anharmonic constants have been deduced from the band-centers of fundamental, overtone, combination, and hot bands of the PF3 gas molecule. Taking into account the Fermi resonance between the ν3 and ν2 + ν4 bands, with a W234 = 2.86 cm–1 coupling term, the band-centers and the anharmonic constants of the molecular potential have been corrected.

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Extending the Applicability of the ANI Deep Learning Molecular Potential to Sulfur and Halogens

10.26434/chemrxiv.11819268.v1 ◽

2020 ◽

Cited By ~ 1

Author(s):

Christian Devereux ◽

Justin Smith ◽

Kate Davis ◽

Kipton Barros ◽

Roman Zubatyuk ◽

...

Keyword(s):

Drug Development ◽

Autonomous Vehicles ◽

Potential Energy Surfaces ◽

Organic Molecules ◽

Chemical Elements ◽

Molecular Potential ◽

Wide Range ◽

Energy Surfaces ◽

New Applications ◽

Physical Phenomena

<p>Machine learning (ML) methods have become powerful, predictive tools in a wide range of applications, such as facial recognition and autonomous vehicles. In the sciences, computational chemists and physicists have been using ML for the prediction of physical phenomena, such as atomistic potential energy surfaces and reaction pathways. Transferable ML potentials, such as ANI-1x, have been developed with the goal of accurately simulating organic molecules containing the chemical elements H, C, N, and O. Here we provide an extension of the ANI-1x model. The new model, dubbed ANI-2x, is trained to three additional chemical elements: S, F, and Cl. Additionally, ANI-2x underwent torsional refinement training to better predict molecular torsion profiles. These new features open a wide range of new applications within organic chemistry and drug development. These seven elements (H, C, N, O, F, Cl, S) make up ~90% of drug like molecules. To show that these additions do not sacrifice accuracy, we have tested this model across a range of organic molecules and applications, including the COMP6 benchmark, dihedral rotations, conformer scoring, and non-bonded interactions. ANI-2x is shown to accurately predict molecular energies compared to DFT with a ~10<sup>6</sup> factor speedup and a negligible slowdown compared to ANI-1x. The resulting model is a valuable tool for drug development that can potentially replace both quantum calculations and classical force fields for myriad applications.</p>

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Anharmonic Coupling Revealed by the Vibrational Spectra of Solvated Protonated Methanol: Fermi Resonance, Combination Bands, and Isotope Effect

The Journal of Physical Chemistry A ◽

10.1021/acs.jpca.1c00068 ◽

2021 ◽

Vol 125 (9) ◽

pp. 1910-1918

Author(s):

Chih-Kai Lin ◽

Qian-Rui Huang ◽

Ying-Cheng Li ◽

Ha-Quyen Nguyen ◽

Jer-Lai Kuo ◽

...

Keyword(s):

Isotope Effect ◽

Vibrational Spectra ◽

Fermi Resonance ◽

Anharmonic Coupling ◽

Combination Bands

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Perturbation Analysis of Quantum Reset Models

Journal of Statistical Physics ◽

10.1007/s10955-021-02752-y ◽

2021 ◽

Vol 183 (1) ◽

Author(s):

Géraldine Haack ◽

Alain Joye

Keyword(s):

Steady State ◽

Perturbation Analysis ◽

Open Quantum Systems ◽

Quantum Systems ◽

Markov Semigroup ◽

Coupling Constant ◽

Coupling Term ◽

Open Quantum ◽

Effective Dynamics ◽

A Chain

AbstractThis paper is devoted to the analysis of Lindblad operators of Quantum Reset Models, describing the effective dynamics of tri-partite quantum systems subject to stochastic resets. We consider a chain of three independent subsystems, coupled by a Hamiltonian term. The two subsystems at each end of the chain are driven, independently from each other, by a reset Lindbladian, while the center system is driven by a Hamiltonian. Under generic assumptions on the coupling term, we prove the existence of a unique steady state for the perturbed reset Lindbladian, analytic in the coupling constant. We further analyze the large times dynamics of the corresponding CPTP Markov semigroup that describes the approach to the steady state. We illustrate these results with concrete examples corresponding to realistic open quantum systems.

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Relativistic treatment of alkaline earth dimers in the presence of non-central molecular potential in N-dimensions

Chemical Physics ◽

10.1016/j.chemphys.2020.111078 ◽

2020 ◽

pp. 111078

Author(s):

Aysen Durmus ◽

Aysel Özfidan

Keyword(s):

Alkaline Earth ◽

Molecular Potential ◽

Relativistic Treatment

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Contact interactions in complex fibrous metamaterials

Continuum Mechanics and Thermodynamics ◽

10.1007/s00161-021-01018-y ◽

2021 ◽

Author(s):

Mario Spagnuolo ◽

Antonio M. Cazzani

Keyword(s):

Strain Energy ◽

Point Of View ◽

The Other ◽

Contact Interactions ◽

Coupling Term ◽

Dissipation Potential ◽

Parallel Fibers ◽

Mathematical Point

AbstractIn this work, an extension of the strain energy for fibrous metamaterials composed of two families of parallel fibers lying on parallel planes and joined by connective elements is proposed. The suggested extension concerns the possibility that the constituent fibers come into contact and eventually scroll one with respect to the other with consequent dissipation due to friction. The fibers interact with each other in at least three different ways: indirectly, through microstructural connections that could allow a relative sliding between the two families of fibers; directly, as the fibers of a family can touch each other and can scroll introducing dissipation. From a mathematical point of view, these effects are modeled first by introducing two placement fields for the two fiber families and adding a coupling term to the strain energy and secondly by adding two other terms that take into account the interdistance between the parallel fibers and the Rayleigh dissipation potential (to account for friction).

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