The hydrogen trioxide (HT) molecule HOOOH is 1) a prototype for a class of molecules of the form X(ZY) with two equivalent internal tops (ZY) and 2) the second representative of the polyoxides series of the form HOH (n ≥ 2). Due to this, it is the subject of close attention of researchers. In this paper, we performed a group theory analysis of the torsional and spin states of the HOOOH, DOOOH, and DOOOD molecules. The relationships have been established between the symmetry species of the C(M) molecular symmetry group to which the HOOOH and DOOOD molecules belong, and the symmetry species of the C and C point groups to which the equilibrium configurations of trans- and cis-conformers of the above molecules belong, respectively. 2D PES and 2D surfaces of kinematic coefficients related to torsional vibrations of hydroxyl groups were calculated at the complete basis set (CBS) limit by extrapolating the results of calculations at the MP2/cc-pVTZ and MP2/cc-pVQZ levels of theory. For all the three molecules, the energies of the stationary torsional states were computed using the Fourier method for a numerical solution of the 2D vibrational Schrödinger equation. Symmetry species of torsional states and the values of quantum numbers defining the types of torsional vibrations were found by analyzing the torsional wave functions. The selection rules for transitions between torsional states in the dipole approximation were also formulated.
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http://dx.doi.org/10.1016/j.saa.2020.118209 | DOI Listing |
J Chem Phys
January 2025
Department of Chemistry, New York University, New York, New York 10003, USA.
The water trimer, as the smallest water cluster in which the three-body interactions can manifest, is arguably the most important hydrogen-bonded trimer. Accurate, fully coupled quantum treatment of its excited intermolecular vibrations has long been an elusive goal. Here, we present the methodology that for the first time allows rigorous twelve-dimensional (12D) quantum calculation of the intermolecular vibration-tunneling eigenstates of the water trimer, with the monomers treated as rigid.
View Article and Find Full Text PDFJ Comput Chem
January 2025
Department of Chemistry, Molecular Sciences Research Hub, Imperial College London, London, UK.
We report nonadiabatic dynamics computations on CH initiated on a coherent superposition of the five lowest cationic states, employing the Quantum Ehrenfest method. In addition to the totally symmetric carbon-carbon double bond stretch and carbon-hydrogen stretches, we see that the three non-totally symmetric modes become stimulated; torsion and three different CH stretching patterns. Thus, a coherent superposition of states, of the type involved in an attochemistry experiment, leads to the stimulation of specific non-totally symmetric motions.
View Article and Find Full Text PDFNat Commun
January 2025
Shanghai Key Laboratory of Molecular Catalysis and Innovation Materials, Collaborative Innovation Centre of Chemistry for Energy Materials, MOE Laboratory for Computational Physical Science, Department of Chemistry, Fudan University, Shanghai, China.
Hybrid density functionals, such as B3LYP and PBE0, have achieved remarkable success by substantially improving over their parent methods, namely Hartree-Fock and the generalized gradient approximation, and generally outperforming the second-order Møller-Plesset perturbation theory (MP2) that is more expensive. Here, we extend the linear scheme of hybrid multiconfiguration pair-density functional theory (HMC-PDFT) by incorporating a cross-entropy ingredient to balance the description of static and dynamic correlation effects, leading to a consistent improvement on both exchange and correlation energies. The B3LYP-like translated on-top functional (tB4LYP) developed along this line not only surpasses the accuracy of its parent methods, the complete active space self-consistent field (CASSCF) and the original MC-PDFT functionals (tBLYP and tB3LYP), but also outperforms the widely used complete active space second-order perturbation theory (CASPT2).
View Article and Find Full Text PDFData Brief
December 2024
Department of Mechanical Engineering, Aalto University, Espoo, Finland.
Accurate system health state prediction through deep learning requires extensive and varied data. However, real-world data scarcity poses a challenge for developing robust fault diagnosis models. This study introduces two extensive datasets, Aalto Shim Dataset and Aalto Gear Fault Dataset, collected under controlled laboratory conditions, aimed at advancing deep learning-based fault diagnosis.
View Article and Find Full Text PDFJ Phys Chem Lett
January 2025
Univ Paris Est Creteil and Université Paris Cité, CNRS, LISA, F-94010 Créteil, France.
Large amplitude motions (LAMs), most notably represented by proton tunneling, mark a significant departure from small amplitude vibrations where protons merely oscillate around their equilibrium positions. These substantial displacements require tunneling through potential energy barriers, leading to splittings in, e.g.
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