Electronic Absorption and Fluorescence Spectra of Matrix-Isolated CoCl2 Molecules

1970 ◽  
Vol 24 (1) ◽  
pp. 53-59 ◽  
Author(s):  
J. R. Clifton ◽  
D. M. Gruen
Keyword(s):  
Absorption Spectrum ◽  
Liquid Helium ◽  
Electronic Absorption ◽  
Fluorescence Spectra ◽  
Axial Ligand ◽  
Ligand Field ◽  
Spin Orbit Coupling ◽  
Spin Orbit ◽  
Absorption And Fluorescence Spectra ◽  
Argon Matrix

The absorption spectrum of CoCl2 molecules isolated in a nitrogen matrix and the fluorescence spectrum of CoCl2 molecules isolated in an argon matrix have been measured at liquid helium temperatures in the range 4000–50 000 cm−1. The absorption and fluorescence spectra in the 4000–25 000 cm−1 region were not mutually observable in the same host. Interpretations of the spectra are given, based on axial ligand field calculations for a 3d7 configuration including spin-orbit coupling interactions.

scholarly journals Theoretical Equations of Zeeman Energy Levels for Distorted Metal Complexes with 3T1 Ground Terms

2019 ◽  
Vol 5 (1) ◽  
pp. 17 ◽  
Author(s):  
Hiroshi Sakiyama
Keyword(s):  
Coupling Parameter ◽  
Energy Levels ◽  
Axial Ligand ◽  
Orbit Coupling ◽  
Ligand Field ◽  
Zero Field ◽  
Spin Orbit Coupling ◽  
Spin Orbit ◽  
Zeeman Energy ◽  
Field Splitting

The theoretical equations of Zeeman energy levels, including the zero-field energies and the first- and second-order Zeeman coefficients, have been obtained in closed form for nine states of the 3 T 1 ( g ) ground term, considering the axial ligand-field splitting and the spin-orbit coupling. The equations are expressed as the functions of three independent parameters, Δ , λ , and κ , where Δ is the axial ligand-field splitting parameter, λ is the spin-orbit coupling parameter, and κ is the effective orbital reduction factor, including the admixing. The equations are useful in simulating magnetic properties (magnetic susceptibility and magnetization) of the complexes with 3 T 1 ( g ) ground terms, e.g., octahedral vanadium(III), octahedral low-spin manganese(III), octahedral low-spin chromium(II), and tetrahedral nickel(II) complexes.

Molecular Vibrations in the Exciton Theory for Molecular Aggregates. II. Dimeric Systems

1961 ◽  
Vol 14 (3) ◽  
pp. 344 ◽  
Author(s):  
EG McRae
Keyword(s):  
Absorption Spectrum ◽  
Perturbation Theory ◽  
Fluorescence Spectra ◽  
Numerical Calculations ◽  
Molecular Vibrations ◽  
Molecular Aggregates ◽  
Absorption And Fluorescence Spectra ◽  
Band Structures ◽  
Electronic Band ◽  
Electronic Band Structures

The theory of Part I of this series (McRae 1961) is developed in detail for dimeric systems. The simplest possible theory of the exciton states for a system of two non-rigid molecules is obtained through the use of perturbation theory. The theory makes possible the prediction of electronic band structures in absorption and fluorescence spectra as functions of the theoretical Davydov splitting for two rigid molecules. Numerical calculations are made for a dimer of a typical dye, and the results are compared with the observed absorption spectrum of the 1,1'-diethyl-2,2'-pyridocyanine iodide dimer.

Polarized Crystal Absorption Spectra of Pd(II) and Pt(II) Tetrahalo and Tetrathiocyanato Complexes

1979 ◽  
Vol 34 (2) ◽  
pp. 211-219
Author(s):  
W. Tuszynski ◽  
G. Gliemann
Keyword(s):  
Single Crystal ◽  
Absorption Spectra ◽  
Theoretical Calculations ◽  
Electron Interaction ◽  
Ultraviolet Region ◽  
Ligand Field ◽  
Spin Orbit Coupling ◽  
Spin Orbit ◽  
Near Ultraviolet ◽  
Spectral Assignment

Abstract Single crystal absorption spectra of tetrachloro, tetrabromo, and tetrathiocyanato complexes of Pd(II) and Pt(II) have been measured in the visible and near-ultraviolet region at temperatures between 10 K and 295 K. A spectral assignment of the observed d-d transitions based on ligand field theoretical calculations including electron-electron interaction and spin-orbit coupling is proposed which is consistent for all the systems investigated

Infrared spectra of tautomers and rotamers of 9-methylguanine. An experimental and theoretical study

1991 ◽  
Vol 69 (11) ◽  
pp. 1705-1720 ◽  
Author(s):  
K. Szczepaniak ◽  
M. Szczesniak ◽  
W. Szajda ◽  
W. B. Person ◽  
J. Leszczynski
Keyword(s):  
Absorption Spectrum ◽  
Ab Initio ◽  
Infrared Spectra ◽  
Electronic Absorption ◽  
Ab Initio Calculation ◽  
Theoretical Study ◽  
Free Energies ◽  
Argon Matrix ◽  
Tautomeric Forms ◽  
Infrared Studies

Both amino-oxo and amino-hydroxy tautomeric forms of 9-methylguanine have been identified in approximately equal abundance in. infrared studies of these molecules isolated in the hydrophobic environment of an argon matrix at 12 K. The amino-hydroxy tautomer occurs in two different rotamers correlated with the rotation of the OH group. The ratio of concentrations of the two rotamers is sensitive to UV irradiation, and this ratio then relaxes to an equilibrium value after irradiation is stopped. This sensitivity allows us to separate the experimental spectra related to the oxo tautomer and to each of the rotamers of the hydroxy tautomer. The relative concentrations of the amino-oxo and amino-hydroxy tautomers ([a-o]/[a-h] = K(o-h) = 1.0 ± 0.3) and of the two rotamers (K(h1-h2) = 0.31 ± 0.10 in an argon matrix at 12 K and about 30 ± 15 in the vapor at 470 K) are estimated from the observed relative infrared absorbances. From these relative concentrations the differences between the free energies of the tautomers (ΔG470 (o-h) = 0 ± 0.5 kJ mol−1) and of the two rotamers (ΔG(h1-h2) = 0.12 ± 0.03 kJ mol−1 in the argon matrix at 12 K and ΔG470 between +2 and −13 kJ mol−1 in the vapor at 470 K) have been estimated. The electronic absorption spectrum of 9-methylguanine isolated in the argon matrix at 12 K and the effect of brief ultraviolet irradiation on it have also been studied. In an effort to interpret the experimental results, ab initio calculations of the infrared spectra have been made for 9-methylguanine at the 3-21G//3-21G level. Comparison with the experimental spectra is of some help with the assignment of the infrared spectra for the different tautomers. Key words: 9-methylguanine, tautomerism, infrared and ultraviolet spectra, matrix isolation, ab initio calculation.

The weak field representation of the crystal field matrices of d4,6 ions and the electronic absorption spectrum of RbFeF3

1969 ◽  
Vol 22 (9) ◽  
pp. 1809 ◽  
Author(s):  
J Ferguson ◽  
HJ Guggenheim ◽  
ER Krausz
Keyword(s):  
Absorption Spectrum ◽  
Electronic Absorption Spectrum ◽  
Crystal Field ◽  
Electronic Absorption ◽  
Strong Field ◽  
Weak Field ◽  
Triplet States ◽  
Spin Orbit ◽  
Crystal Field Theory ◽  
Field Representation

The electronic absorption spectrum of RbFeF3 is reported and analysed by means of crystal field theory. It is shown that the strong field formalism is limited for high spin Fe2+ and the weak field representation should be used to interpret the many triplet states. Published spin-orbit weak field matrices for d4,6 are shown to contain errors. The weak field matrices in the absence of spin-orbit coupling have been derived and they are used to assign the spectrum of RbFeF3.

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