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.

Crystal field spectra of d3,7 ions. IV. The weak field representation of the spin-orbit matrices

1970 ◽  
Vol 23 (4) ◽  
pp. 635 ◽  
Author(s):  
J Ferguson
Keyword(s):  
Absorption Spectrum ◽  
Crystal Field ◽  
Weak Field ◽  
Spin Orbit ◽  
Field Representation

The spin-orbit crystal field matrices for d3,7 are given in the weak field repre- sentation. They are used to assign the crystal absorption spectrum of CoSiF6,6H2O.

Crystal field spectra of d3,7 ions. VI. The weak field formalism and covalency

1970 ◽  
Vol 23 (5) ◽  
pp. 861 ◽  
Author(s):  
J Ferguson ◽  
DL Wood
Keyword(s):  
Crystal Field ◽  
Strong Field ◽  
Energy Levels ◽  
Outer Part ◽  
Weak Field ◽  
Field Energy ◽  
Electrostatic Repulsion ◽  
Crystal Field Theory ◽  
Free Ion ◽  
Field Formalism

When the problem of an ion in a crystal field is solved using the unperturbed atomic wave functions as basis functions, the free ion energies appear explicitly in the diagonal terms of the secular determinant where they can be adjusted as experimental parameters. By fitting the observed crystal field energy levels in this scheme, a set of modified free ion energy levels can be derived for Dq = 0, and it is found that in most cases a single set of electrostatic repulsion parameters F2 and F4 describes the energies, provided a Trees correction is applied. The values of F2 and F4 obtained in this way from crystal spectra of Cr3+ in ruby, yttrium gallium garnet, other oxides, and K3Cr(CN)6 and of Co2+ in ZnAl2O4 are reduced by covalency from their free ion values. The reduction for P2 is greater than for F4 because of its greater sensitivity to the outer part of the radial distribution function, where covalency plays its major part. It is concluded that the differential expansion of the t2 and e orbitals in the crystal field is not great, and that nephelauxetic effects in crystal field spectra should more properly be related to the F2 and F4 parameters of Condon and Shortley through the weak field formalism, rather than to Racah's B parameter in the strong field approach. The latter results in unsound conclusions about the effects of covalency. Analysis of the spectra of CrBrs and C0C14" suggests that the d electrons are not adequately described by two electrostatic repulsion parameters and the usual crystal field theory should be applied cautiously.

Ortho effects on the change in electronic absorption spectrum of pyridinium salts of saturated bromohydrocarbon

2009 ◽  
Vol 74 (5) ◽  
pp. 1084-1089 ◽  
Author(s):  
Jin-Ling Song ◽  
Li-Ming Gong ◽  
Shou-Ai Feng ◽  
Jiang-Hong Zhao ◽  
Jian-Feng Zheng ◽  
...  
Keyword(s):  
Absorption Spectrum ◽  
Electronic Absorption Spectrum ◽  
Electronic Absorption ◽  
Pyridinium Salts

The electronic spectra of phenyl radicals

1965 ◽  
Vol 287 (1411) ◽  
pp. 457-470 ◽  
Keyword(s):  
Absorption Spectrum ◽  
Electronic Absorption Spectrum ◽  
Electronic Absorption ◽  
Ground State ◽  
Electronic Spectra ◽  
Flash Photolysis ◽  
Visible Region ◽  
Electronic Configuration ◽  
Vibrational Structure ◽  
Fundamental Frequencies

An electronic absorption spectrum, attributed to phenyl, has been observed in the visible region with origin at 18 908 cm -1 after flash photolysis of benzene and halogenobenzenes. Similar spectra of fluoro, chloro and bromo phenyl are observed after flash photolysis of disubstituted benzenes. The vibrational structure of the phenyl spectrum has been analysed in terms of two fundamental frequencies at 571 and 896 cm -1 which correspond to the e 2 g and a 1 g frequencies of the B 2 u state of benzene. The ground state of phenyl has a π 6 n electronic configuration and the observed transition is interpreted as 2 A 1 → 2 B 1 resulting from a π → n excitation.

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