All-electron relativistic spin–orbit multireference computation to elucidate the ground state of CeH

2020 ◽  
Vol 22 (46) ◽  
pp. 27157-27162
Author(s):  
Yusuke Kondo ◽  
Yuri Goto ◽  
Masato Kobayashi ◽  
Tomoko Akama ◽  
Takeshi Noro ◽  
...  

The all-electron relativistic spin–orbit multiconfiguration/multireference computations with the Sapporo basis sets were carried out to elucidate the characters of the low-lying quasi-degenerate electronic states for the CeH diatomic molecule.

2002 ◽  
Vol 80 (9) ◽  
pp. 1025-1035 ◽  
Author(s):  
M Korek ◽  
A R Allouche ◽  
S N Abdul Al

The KCs+ molecular ion potential curves are investigated over a wide range of internuclear distance for electronic states described in a 2Λ(+) representation (neglecting the spin-orbit effect) as well as in an Ω(+) representation (including the spin-orbit effect). This calculation has been done in a one active electron approach by using an ab initio method based on non-empirical pseudopotentials with core-valence effect taken into account through parameterized l-dependent polarization potentials. Gaussian basis sets have been used for both atoms, and spin-orbit effects have been taken into account through a semiempirical spin-orbit pseudopotential. The canonical functions approach is used to do a rovibrational study by calculating the eigenvalues Ev, the rotational constant Bv, the centrifugal distortion constants Dv (up to 106 vibrational levels), and the spectroscopic constants are deduced for six bound states. The permanent and transition dipole moment functions have been derived for transitions between the bound states 2 Σ+ and 2Π as well as the oscillator strengths for the transitions v = 0, 10, 20, and Δ v = 0, 1, 2, ..., 6. To the best of our knowledge neither theoretical nor experimental data are available in the literature for the molecular ion KCs+. Extensive tables of Ev, Bv, Dv, and the energy values versus internuclear distance are displayed at the following address: http://hplasim2.univ-lyon1.fr/allouche/kcsplus.html. PACS Nos.: 33.15Dj, 33.20wr


2009 ◽  
Vol 87 (10) ◽  
pp. 1079-1088 ◽  
Author(s):  
N. Elkork ◽  
D. Houalla ◽  
M. Korek

The potential energy curves of the molecule LiCs have been calculated for the 55 low-lying electronic states in the Ω-representation. Using an ab initio method the calculation is based on a nonempirical pseudo-potential in the interval 3.0ao≤ R ≤ 40.0ao of the internuclear distance. The spin–orbit effects have been taken into account through a semi-empirical spin–orbit pseudo-potential added to the electrostatic Hamiltonian with Gaussian basis sets for both atoms. The spectroscopic constants have been calculated for 39 states and the components of the spin–orbit splitting have been identified for the states (2, 5)3Π and (1)3Δ. The comparison of the present results with those available in literature shows good agreement, while the other results, to the best of our knowledge, are given here for the first time.


2008 ◽  
Vol 86 (8) ◽  
pp. 1015-1022 ◽  
Author(s):  
M Korek ◽  
K Badreddine ◽  
A R Allouche

A theoretical study was done of the electronic structure of the molecular ion NaCs+. The calculation is based on nonempirical pseudopotentials and parameterized [Formula: see text]-dependent polarization potential. Gaussian basis sets were used for both atoms and spin-orbit effects were taken into account. Potential energy curves were obtained for 56 lowest electronic states for the symmetries 2∑+, 2Π, 2Δ, and Ω of the molecular ion NaCs+. The spectroscopic constants were calculated for 19 electronic states by fitting the calculated energy values to polynomials in terms of the internuclear distance r. Through the canonical functions approach the eigenvalue Ev, the rotational constant Bv and the abscissas of the turning points were calculated up to 52 vibrational levels for 6 bound states. The dipole moment were calculated in the considered range of the internuclear distance r. The comparison of the calculated values to those available in the literature shows a good agreement. PACS Nos.: 31.10.+z, 31.15.Ar, 31.50.Df, 33.15.Mt


Author(s):  
Kenneth G. Dyall ◽  
Knut Faegri

This book provides an introduction to the essentials of relativistic effects in quantum chemistry, and a reference work that collects all the major developments in this field. It is designed for the graduate student and the computational chemist with a good background in nonrelativistic theory. In addition to explaining the necessary theory in detail, at a level that the non-expert and the student should readily be able to follow, the book discusses the implementation of the theory and practicalities of its use in calculations. After a brief introduction to classical relativity and electromagnetism, the Dirac equation is presented, and its symmetry, atomic solutions, and interpretation are explored. Four-component molecular methods are then developed: self-consistent field theory and the use of basis sets, double-group and time-reversal symmetry, correlation methods, molecular properties, and an overview of relativistic density functional theory. The emphases in this section are on the basics of relativistic theory and how relativistic theory differs from nonrelativistic theory. Approximate methods are treated next, starting with spin separation in the Dirac equation, and proceeding to the Foldy-Wouthuysen, Douglas-Kroll, and related transformations, Breit-Pauli and direct perturbation theory, regular approximations, matrix approximations, and pseudopotential and model potential methods. For each of these approximations, one-electron operators and many-electron methods are developed, spin-free and spin-orbit operators are presented, and the calculation of electric and magnetic properties is discussed. The treatment of spin-orbit effects with correlation rounds off the presentation of approximate methods. The book concludes with a discussion of the qualitative changes in the picture of structure and bonding that arise from the inclusion of relativity.


1959 ◽  
Vol 37 (2) ◽  
pp. 136-143 ◽  
Author(s):  
Nand Lal Singh

The fine structures of three of the β bands of PO which occur near 3200 Å have been analyzed. The analysis shows that the upper state of this band system is a 2Σ and not a 2Π state as previously believed. The rotational constants of both electronic states have been determined and it is found that the ground state constants, previously determined from the γ bands, are incorrect.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
S. Menouer ◽  
O. Miloud Abid ◽  
A. Benzair ◽  
A. Yakoubi ◽  
H. Khachai ◽  
...  

AbstractIn recent years the intermetallic ternary RE2MgGe2 (RE = rare earth) compounds attract interest in a variety of technological areas. We therefore investigate in the present work the structural, electronic, magnetic, and thermodynamic properties of Nd2MgGe2 and Gd2MgGe2. Spin–orbit coupling is found to play an essential role in realizing the antiferromagnetic ground state observed in experiments. Both materials show metallicity and application of a Debye-Slater model demonstrates low thermal conductivity and little effects of the RE atom on the thermodynamic behavior.


Author(s):  
Shuang Yin ◽  
Xiang Yuan ◽  
Yong Liu ◽  
Haifeng Xu ◽  
Bing Yan

1982 ◽  
Vol 26 (4) ◽  
pp. 1984-1987 ◽  
Author(s):  
Y. -K. Kim ◽  
K. -N. Huang
Keyword(s):  

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