Transition energies and oscillator strengths for electronic spectra of non planar conjugated molecules. I. Polyphenyls

1973 ◽  
Vol 29 (4) ◽  
pp. 335-343 ◽  
Author(s):  
A. Gamba ◽  
G. F. Tantardini ◽  
M. Simonetta
Keyword(s):  
Electronic Spectra ◽  
Oscillator Strengths ◽  
Conjugated Molecules ◽  
Transition Energies

Semiempirische SCF-Rechnungen zur Hydroxypyridin-Pyridon-Tautomerie / Semiempirical SCF-Calculations on the Hydroxypyridine-Pyridone-Tautomerism

1979 ◽  
Vol 34 (2) ◽  
pp. 266-270 ◽  
Author(s):  
Walter Fabian
Keyword(s):  
Electronic Spectra ◽  
Transition Energies ◽  
Scf Calculations

Abstract The electronic spectra of a series of substituted 4-hydroxypyridones are calculated by the CNDO/CI-method. Best agreement between observed and calculated transition energies is obtained when the geometry of the pyridone-form is assumed. In addition, MINDO/2-calculations predict the pyridone tautomer to be the more stable one in most cases.

Single crystal electronic spectra of a series of trans nickel(II) complexes with N,N′-diethyl- and N,N′-dimethylethylenediamine

1977 ◽  
Vol 55 (17) ◽  
pp. 3172-3189 ◽  
Author(s):  
A. B. P. Lever ◽  
G. London ◽  
P. J. McCarthy
Keyword(s):  
Steric Hindrance ◽  
Electronic Spectra ◽  
Spherical Harmonic ◽  
Bonding Strength ◽  
Ligand Field ◽  
Transition Energies ◽  
B Values ◽  
Axial Ligands ◽  
Symmetry Adapted Functions ◽  
Spectrochemical Series

We have measured the polarized crystal spectra at 10 K. of Ni(s-Et2en)2X2, where X = Cl, Br, NCS, and H2O (with Cl, Br, and I counterions) and *-Et2en is N, N'-diethylethylenediamine, and of Ni(s-Me2en)2X2, where X = NCS and NO3, and.s-Me2en is N,N′-dimethylethylenediamine. Transition energies were calculated for D4h symmetry using symmetry adapted functions and a normalized spherical harmonic Hamiltonian. When the differences between calculated and observed band positions are minimized, the ligand-field and angular overlap parameters listed in Table 2 are obtained. The criteria for the band assignments are discussed. The principal conclusions are: (1) The π interactions between Ni(II) and the axial ligands are small in contrast to tetragonal Cr(III) complexes. (2) Equatorial and axial parameters are relatively independent, in contrast to tetragonal Cu(II) complexes. (3) The more basic,s-Et2en exerts a stronger ligand field than,s-Me2en. (4) The σ-bonding strength of the axial ligands follows the spectrochemical series. (5) DQ for the axial ligands in the ethyl complexes is lower than anticipated, probably due to steric hindrance of the bulky ethyl groups. (6) B values are all near 850 cm−1, except for an anomalously low value for Ni(s-Et2en)2(NCS)2.

LCAO MO Investigations on Lignin Model Compounds VI. CNDO/CI Calculations of Electronic Spectra of Cinnamaldehyde Structures

1978 ◽  
Vol 33 (1) ◽  
pp. 59-65 ◽  
Author(s):  
Milan Remko ◽  
Jan Polčin
Keyword(s):  
Electronic Absorption ◽  
Electronic Spectra ◽  
Electronic Absorption Spectra ◽  
Model Compounds ◽  
Lignin Model Compounds ◽  
Transition Energies ◽  
Lignin Model ◽  
Ci Calculations ◽  
Good Agreement ◽  
Lcao Mo

The electronic absorption spectra of cinnamaldehyde, o-, m-, p-hydroxycinnamaldehyde and 3-methoxy-4-hydroxy cinnamaldehyde were theoretically and experimentally studied, by means of the semiempirical CNDO/CI method. The calculated and observed transition energies were in good agreement.

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