Molecular symmetry: Why permutation-inversion (PI) groups don’t render the point groups obsolete

Groner, P.

doi:10.1016/j.jms.2017.07.011

Cited by 4 publications

(1 citation statement)

References 53 publications

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“…It is not the purpose of the present work to give a detailed review of all the symmetry properties of a given molecule and to study how the vibration-LAM-rotation wave functions transform in the operations of a symmetry group. Extensive group-theoretical considerations can be found for example in the excellent reviews 66,67,69,73,74,[106][107][108] Non-tunnelling molecules: for molecules where no tunnelling splitting is observed, the extension of TENSOR to the MS groups is direct because of their isomorphism with the point groups. However, the MS group is not necessarily the same as the CNPI group.…”

Section: Symmetry Considerationsmentioning

confidence: 99%

A numerical-tensorial “hybrid” nuclear motion Hamiltonian and dipole moment operator for spectra calculation of polyatomic nonrigid molecules

Rey,

Viglaska,

Egorov

et al. 2023

The Journal of Chemical Physics

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The analysis and modeling of high-resolution spectra of nonrigid molecules require a specific Hamiltonian and group-theoretical formulation that differs significantly from that of more familiar rigid systems. Within the framework of Hougen–Bunker–Johns (HBJ) theory, this paper is devoted to the construction of a nonrigid Hamiltonian based on a suitable combination of numerical calculations for the nonrigid part in conjunction with the irreducible tensor operator method for the rigid part. For the first time, a variational calculation from ab initio potential energy surfaces is performed using the HBJ kinetic energy operator built from vibrational, large-amplitude motion, and rotational tensor operators expressed in terms of curvilinear and normal coordinates. Group theory for nonrigid molecules plays a central role in the characterization of the overall tunneling splittings and is discussed in the present approach. The construction of the dipole moment operator is also examined. Validation tests consisting of a careful convergence study of the energy levels as well as a comparison of results obtained from independent computer codes are given for the nonrigid molecules CH2, CH3, NH3, and H2O2. This work paves the way for the modeling of high-resolution spectra of larger nonrigid systems.

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Section: Symmetry Considerationsmentioning

confidence: 99%

A numerical-tensorial “hybrid” nuclear motion Hamiltonian and dipole moment operator for spectra calculation of polyatomic nonrigid molecules

Rey,

Viglaska,

Egorov

et al. 2023

The Journal of Chemical Physics

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Torsional splitting and the four-fold barrier to internal rotation: The rotational spectra of vinylsulfur pentafluoride

Orellana

Stephens

Pringle

et al. 2018

The Journal of Chemical Physics

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Vinylsulfur pentafluoride (VSPF), a molecule with a four-fold internal rotor, —SF4, has been studied with high resolution Fourier transform microwave spectroscopy. We believe that this is the first report of resolved four-fold internal rotation. As such, we have presented the tools needed to understand and analyze such a problem. These include debugging the ERHAM computer program necessary to fit the spectra and the free rotor to high barrier correlation diagram necessary to understand the torsional states of the four-fold rotor. The A, E, and B torsional state rotational transitions are well resolved and assigned. Spectroscopic transitions of four isotopologues of VSPF, H2C=CH—SF5, the normal isotopologue, and the singly substituted 34S and 13C isotopologues were measured and assigned. Contrary to expectation, the A torsional state could not be fit with only a semi-rigid Hamiltonian. The barrier to internal rotation, V4, is found to be 227 cm−1. Ab initio calculations at the MP2 aug-cc-pVQZ level of theory and basis set were performed and the results of this calculation are compared to our experimental results.

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Investigation of the ν₈and ν₂₁bands of propane CH₃CH₂CH₃at 11.5 and 10.9 µm: evidence of large amplitude tunnelling effects

et al. 2018

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Molecular symmetry: Why permutation-inversion (PI) groups don’t render the point groups obsolete

Cited by 4 publications

References 53 publications

A numerical-tensorial “hybrid” nuclear motion Hamiltonian and dipole moment operator for spectra calculation of polyatomic nonrigid molecules

A numerical-tensorial “hybrid” nuclear motion Hamiltonian and dipole moment operator for spectra calculation of polyatomic nonrigid molecules

Torsional splitting and the four-fold barrier to internal rotation: The rotational spectra of vinylsulfur pentafluoride

Investigation of the ν₈and ν₂₁bands of propane CH₃CH₂CH₃at 11.5 and 10.9 µm: evidence of large amplitude tunnelling effects

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Molecular symmetry: Why permutation-inversion (PI) groups don’t render the point groups obsolete

Cited by 4 publications

References 53 publications

A numerical-tensorial “hybrid” nuclear motion Hamiltonian and dipole moment operator for spectra calculation of polyatomic nonrigid molecules

A numerical-tensorial “hybrid” nuclear motion Hamiltonian and dipole moment operator for spectra calculation of polyatomic nonrigid molecules

Torsional splitting and the four-fold barrier to internal rotation: The rotational spectra of vinylsulfur pentafluoride

Investigation of the ν8and ν21bands of propane CH3CH2CH3at 11.5 and 10.9 µm: evidence of large amplitude tunnelling effects

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Investigation of the ν₈and ν₂₁bands of propane CH₃CH₂CH₃at 11.5 and 10.9 µm: evidence of large amplitude tunnelling effects