The Discrete Spectrum�of the Perturbed Periodic Schr�dinger Operator�in the Large Coupling Constant Limit

2001 ◽  
Vol 218 (1) ◽  
pp. 217-232 ◽  
Author(s):  
Oleg Safronov
Keyword(s):  
Discrete Spectrum ◽  
Coupling Constant ◽  
Large Coupling ◽  
Large Coupling Constant ◽  
Perturbed Periodic

scholarly journals Preparation and Spectroscopic Characterization of trans-Fe(CO)3L1L2 (L1, L2 = Phosphine or Phosphite)

1989 ◽  
Vol 44 (6) ◽  
pp. 641-646 ◽  
Author(s):  
Hidenari Inoue ◽  
Takeshi Kuroiwa ◽  
Tsuneo Shirai ◽  
Ekkehard Fluck
Keyword(s):  
Spectroscopic Characterization ◽  
Coupling Constant ◽  
Positive Slope ◽  
Phosphorus Ligands ◽  
Large Coupling ◽  
Iron Carbonyls ◽  
Trigonal Bipyramidal ◽  
Large Coupling Constant ◽  
Back Donation

The 57Fe Mößbauer spectra of mixed ligand complexes of the type trans-Fe(CO)3L1L2 (L1 = triphenylphosphine or triphenylphosphite and L2 = phosphine or phosphite) show a quadrupolesplitting doublet typical of the disubstituted iron carbonyls in trigonal bipyramidal symmetry. The inverse linear dependence of the isomer shifts on the CO stretching frequencies is interpreted on the basis of the strengthening triple-bond nature of the carbonyl ligands with increasing iron-to-phosphorus π-back donation. A linear correlation, with a positive slope, between the isomer shifts and the quadrupole splittings has revealed that the phosphorus-to-iron σ-donation is offset by the iron-to-phosphorus π-back donation. A correlation between the coordination shifts and the isomer shifts demonstrates that the iron-to-phosphorus π-back donation plays an important role in the Fe-P bond. The relatively large coupling constant of 2J(P,P) reflects a strong interaction between trans-phosphorus ligands through the P-Fe-P bond

PHASE STRUCTURE OF THREE- AND FOUR-DIMENSIONAL ϕ4 FIELD THEORY

1992 ◽  
Vol 07 (19) ◽  
pp. 4539-4558 ◽  
Author(s):  
G.V. EFIMOV ◽  
S.N. NEDELKO
Keyword(s):  
Field Theory ◽  
Renormalization Group ◽  
Strong Coupling ◽  
Phase Structure ◽  
Space Time ◽  
Strong Coupling Regime ◽  
Canonical Transformations ◽  
Coupling Constant ◽  
Large Coupling ◽  
Large Coupling Constant

The strong coupling regime of gϕ4 theory in space-time Rd for d=3, 4 is investigated by the methods of canonical transformations and the renormalization group. It is shown that the model describes a system symmetric under transformation ϕ→−ϕ both at small and large coupling constant g. Comparison with the case d=2 shows a crucial influence of the renormalization structure of the theory on its phase structure.

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