Spectre du radical P2+ : Etude des transitions C2Π – X2Π et D2Π–X2Π

1976 ◽  
Vol 54 (8) ◽  
pp. 907-914 ◽  
Author(s):  
J. Malicet ◽  
J. Brion ◽  
H. Guenebaut

The emission spectrum of the P2+ molecular ion has been obtained with a high frequency discharge through a mixture of helium and phosphorus vapour. Both the C2Π–X2Π and D2Π–X2Π systems have been photographed under high dispersion and their rotational structure analysed.The previously known C2Π–X2Π system has been completed by analysing 21 new bands. The D2Π(inv)–X2Π system has not been observed previously. For the three states, involved in these two transitions, the vibrational and rotational constants have been calculated or refined. The p constants for the Λ-doubling for each state have been evaluated. Finally the interpretation of the data of the C2Π state requires a centrifugal distortion term AD in the spin–orbit coupling constant A.


1981 ◽  
Vol 59 (12) ◽  
pp. 1851-1861 ◽  
Author(s):  
A. Jenouvrier ◽  
B. Pascat

The deperturbed vibration–rotation constants of the A2Π and X2Σ+ states of BS are obtained. The perturbations in the levels of the A2Π state observed in the A2Π–X2Σ+ system are treated and are the result of interactions with high levels of the X2Σ+ state. The electronic factors of the spin–orbit and rotation–electronic perturbation matrix elements for the A ~ X interaction are evaluated. The deperturbed spin–orbit coupling constant of the A state is determined.



1975 ◽  
Vol 53 (4) ◽  
pp. 420-423 ◽  
Author(s):  
H. R. Zaidi ◽  
R. D. Verma

Expressions are derived for the spin–orbit coupling constant, AvJ, for an isolated 2Π state of a diatomic molecule. These results are applied to the X2Π states of PO. Comparison with the available experimental results allows a determination of the first three derivatives of the coupling parameter at the equilibrium position. It is found that the second derivative gives the largest contribution, thus invalidating a common assumption of the existing theories.



1977 ◽  
Vol 55 (10) ◽  
pp. 937-942 ◽  
Author(s):  
A. F. Leung ◽  
Ying-Ming Poon

The absorption spectra of UCl5 single crystal were observed in the region between 0.6 and 2.4 μm at room, 77, and 4.2 K temperatures. Five pure electronic transitions were assigned at 11 665, 9772, 8950, 6643, and 4300 cm−1. The energy levels associated with these transitions were identified as the splittings of the 5f1 ground configuration under the influence of the spin–orbit coupling and a crystal field of C2v symmetry. The number of crystal field parameters was reduced by assuming the point-charge model where the positions of the ions were determined by X-ray crystallography. Then, the crystal field parameters and the spin–orbit coupling constant were calculated to be [Formula: see text],[Formula: see text], [Formula: see text], and ξ = 1760 cm−1. The vibronic analysis showed that the 90, 200, and 320 cm−1 modes were similar to the T2u(v6), T1u(v4), and T1u(v3) of an UCl6− octahedron, respectively.



1972 ◽  
Vol 50 (10) ◽  
pp. 1468-1471 ◽  
Author(s):  
Alan D. Westland

An expression for the magnetic susceptibility of octahedral d1 complexes is derived exactly in terms of an orbital reduction factor k taking into account the presence of the formal 2E excited state. Sample calculations show that the improved expression gives results for susceptibility which are lower at times by several percent from those given by previous expressions. The results given by Figgis using Kotani's method are adequately precise when the spin–orbit coupling constant is no larger than ~0.1 Dq.



1974 ◽  
Vol 52 (9) ◽  
pp. 813-820 ◽  
Author(s):  
René Stringat ◽  
Jean-Paul Bacci ◽  
Marie-Hélène Pischedda

The strongly perturbed 1Π–X1Σ+ system of C80Se has been observed in the emission spectrum of a high frequency discharge through selenium and carbon traces in a neon atmosphere. The analysis of five bands yields, for the molecular constants of the ground state, the values Be″ = 0.5750 cm−1, [Formula: see text], αe″ = 0.00379 cm−1, re″ = 1.676 Å, ΔG″(1/2) = 1025.64 cm−1, and ΔG″(3/2) = 1015.92 cm−1. The numerous perturbations in the 1Π state prohibit the simple evaluation of the constants of the perturbed state and of the perturbing ones.



1984 ◽  
Vol 80 (6) ◽  
pp. 2401-2406 ◽  
Author(s):  
Martin Vala ◽  
Kyle Zeringue ◽  
Jalal ShakhsEmampour ◽  
Jean‐Claude Rivoal ◽  
Robert Pyzalski


Results of calculations of the spin-orbit coupling constant for 2 p , 3 p , 4 p , and 3 d shell ions and atoms are presented. The calculations are based on a theory developed in a previous paper. Excellent agreement of this theory with experiment is obtained for the 2 p and 3 d shell ions, while calculations using the familiar < ∂ V / r ∂ r > expression for the coupling constant lie 10 to 20 % too high. The exchange terms discussed in the earlier paper make a contribution to the coupling constant of the same sign and order of magnitude as the ordinary shielding terms. For the 3 p and 4 p shell atoms, the calculated coupling constants based on the exact theory and on the < ∂ V / r ∂ r > expression both tend to lie below the experimental values. An explanation for this disagreement is suggested, based on the noded nature of the outer-electron radial wave functions for these atoms. The importance of the residual-spin-other-orbit interaction is discussed, and it is shown that ignoring the form of this interaction may lead to a large variation in the coupling constant within a configuration.



An exact expression for the spin-orbit coupling constant is derived within the Hartree-Fock description of the atom by considering the two body mutual spin-orbit interaction between electrons. The interaction is rewritten in tensor operator form and the contribution of outer electron-core interactions to the coupling constant is calculated. We find that the usual expression < 3F/r8r > where V is the Hartree potential is only approximate, and that certain exchange type terms, which arise because we are dealing with a two-body interaction and determinantal wave function, must also be included. These exchange terms are not simply related to the ordinary electrostatic exchange. The resulting expression for the spin-orbit coupling constant is given in terms of radial integrals which can be calculated using Hartree or Hartree—Fock wave functions. We also discuss the effective magnetic Hamiltonian to be used for the calculation of matrix elements within an atomic configuration.



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