scholarly journals Calculation of electric quadrupole linestrengths for diatomic molecules: Application to the H2, CO, HF and O2 molecules

2021 ◽  
Author(s):  
Wilfrid Somogyi ◽  
Sergey Yurchenko ◽  
Andrey Yachmenev
Keyword(s):  
Diatomic Molecules ◽  
Electric Quadrupole

An alternative mechanism for spin-forbidden photo-ionization of diatomic molecules and its rotation–electronic selection rules

1990 ◽  
Vol 68 (2) ◽  
pp. 177-183 ◽  
Author(s):  
Ying-Nan Chiu ◽  
Lue-Yung Chow Chiu
Keyword(s):  
Diatomic Molecules ◽  
Rotational Level ◽  
Electric Quadrupole ◽  
Chem Phys ◽  
Electric Dipole Transition ◽  
Wave Functions ◽  
Alternative Mechanism ◽  
Selection Rules ◽  
Photon Ionization ◽  
Photo Ionization

The spin-forbidden photo-ionization of diatomic molecules is proposed. Spin orbit interaction is invoked resulting in the correction and mixing of the wave functions of different multiplicities. The rotation–electronic selection rules given, but not proven, by Dixit and McKoy for Hund's case a based on the conventional mechanism of electric dipole transition (see Chem. Phys. Lett. 128, 49 (1986) are rederived and expressed in a different format. This new format permits the generalization of the selection rules to other photo-ionization transitions caused by the magnetic dipole, the electric quadrupole, and the two- and three-photon operators. These selection rules, which are for transitions from one specific rotational level of a given Kronig reflection symmetry to another, will help understand rotational branching and the dynamics of interaction in the excited state. They will also help in the selective preparation of well-defined rovibronic states in resonant-enhanced multi-photon ionization processes.

Magnetic hyperfine interactions in the electronic spectra of diatomic molecules II. Magnetic interactions in Hund’s case ( c ) and the spectram of BiO

1967 ◽  
Vol 300 (1463) ◽  
pp. 487-495 ◽  
Keyword(s):  
Hyperfine Interaction ◽  
Diatomic Molecules ◽  
Hyperfine Interactions ◽  
Electric Quadrupole ◽  
Magnetic Interactions ◽  
Magnetic Hyperfine ◽  
Matrix Elements ◽  
Magnetic Hyperfine Interaction ◽  
Angular Momenta ◽  
The Matrix

The magnetic hyperfine interaction in Hund’s case ( c ) diatomic molecules is investigated by the method of spherical tensors and time-reversed angular momenta. Explicit expressions for the matrix elements are given, so too are expressions for the first and second order energies for an |Ω| = 1/2 state. The equations are applied to the electronic spectrum of BiO (Barrow, Gissane & Richards 1967) and the observed line widths are accounted for in terms of a magnetic hyperfine interaction with the 209 Bi nucleus. The electric quadrupole hyperfine interaction in BiO is also investigated and shown to be incapable of accounting for the observed effects.

Density functionals and chemical bond, diatomic molecules

1989 ◽  
Vol 86 ◽  
pp. 853-859 ◽  
Author(s):  
Federico Moscardó ◽  
José Pérez-Jordá ◽  
Emilio San-Fabián
Keyword(s):  
Chemical Bond ◽  
Diatomic Molecules ◽  
Density Functionals

The Deformation Structure of the Nuclei 32S and 36Ar

2017 ◽  
Vol 13 (2) ◽  
pp. 4678-4688
Author(s):  
K. A. Kharroube
Keyword(s):  
Single Particle ◽  
Electric Quadrupole ◽  
Quadrupole Moments ◽  
Moments Of Inertia ◽  
Deformation Structures ◽  
Particle Potential ◽  
Nilsson Model ◽  
Single Particle Potential ◽  
Axes Of Symmetry ◽  
Good Agreement

We applied two different approaches to investigate the deformation structures of the two nuclei S32 and Ar36 . In the first approach, we considered these nuclei as being deformed and have axes of symmetry. Accordingly, we calculated their moments of inertia by using the concept of the single-particle Schrödinger fluid as functions of the deformation parameter β. In this case we calculated also the electric quadrupole moments of the two nuclei by applying Nilsson model as functions of β. In the second approach, we used a strongly deformed nonaxial single-particle potential, depending on Î² and the nonaxiality parameter γ , to obtain the single-particle energies and wave functions. Accordingly, we calculated the quadrupole moments of S32 and Ar36 by filling the single-particle states corresponding to the ground- and the first excited states of these nuclei. The moments of inertia of S32 and Ar36 are then calculated by applying the nuclear superfluidity model. The obtained results are in good agreement with the corresponding experimental data.

Full Optical Rotation Tensor at CCSD Level in the Modified Velocity Gauge

2020 ◽  
Author(s):  
Kaihua Zhang ◽  
Ty Balduf ◽  
Marco Caricato
Keyword(s):  
Electric Dipole ◽  
Optical Rotation ◽  
Electric Quadrupole ◽  
Polarizability Tensor ◽  
Dipole Polarizability ◽  
Difficult Case ◽  
Computationally Efficient ◽  
Rotation Tensor ◽  
Approximate Methods ◽  
Velocity Gauge

<div> <div> <p> </p><div> <div> <div> <p>This work presents the first simulations of the full optical rotation (OR) tensor at coupled cluster with single and double excitations (CCSD) level in the modified velocity gauge (MVG) formalism. The CCSD-MVG OR tensor is origin independent, and each tensor element can in principle be related directly to experimental measurements on oriented systems. We compare the CCSD results with those from two density functionals, B3LYP and CAM-B3LYP, on a test set of 22 chiral molecules. The results show that the functionals consistently overestimate the CCSD results for the individual tensor components and for the trace (which is related to the isotropic OR), by 10-20% with CAM-B3LYP and 20-30% with B3LYP. The data show that the contribution of the electric dipole-magnetic dipole polarizability tensor to the OR tensor is on average twice as large as that of the electric dipole-electric quadrupole polarizability tensor. The difficult case of (1S,4S)-(–)-norbornenone also reveals that the evaluation of the former polarizability tensor is more sensitive than the latter. We attribute the better agreement of CAM-B3LYP with CCSD to the ability of this functional to better reproduce electron delocalization compared with B3LYP, consistently with previous reports on isotropic OR. The CCSD-MVG approach allows the computation of reference data of the full OR tensor, which may be used to test more computationally efficient approximate methods that can be employed to study realistic models of optically active materials. </p> </div> </div> </div> </div> </div>

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