| 1. |
- Dahlgren, T., et al.
(author)
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Electronic spectra of dithieno analogues of phenanthrene
- 1979
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In: Chemical Physics. - : Elsevier BV. - 0301-0104. ; 40:3, s. 397-404
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Journal article (peer-reviewed)abstract
- The magnetic circular dichroism (MCD) spectra of some dithieno analogues of phenanthrene: benzo [2,1-b;3,4-b′] dithiophene (I) benzo [1,2-b;4,3-b′] dithiophene (II), benzo [1,2-c;3,4-c′] dithiophene (III) and benzo [1,2-b;3,4-b′] dithiophene (IV) are reported. For I–III the spectra corresponding to two different transition moment directions could be obtained from low-temperature linear dichroism spectra. The results compare well with theoretical energies, oscillator strengths, moment directions and MCD B-terms which were obtained from semi-empirical quantum mechanical calculations in the π-electron approximation.
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| 2. |
- Davidsson, A., et al.
(author)
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A method for determination of the refractive index in a region of absorption. Anomalous dispersion of CS2 in the UV range
- 1975
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In: Chemical Physics. - : Elsevier BV. - 0301-0104. ; 8:1-2, s. 223-230
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Journal article (peer-reviewed)abstract
- A method is described for determining the refractive index of, e.g., a liquid solution, within an absorption band by studying the linear dichroism generated by different reflections at inclined optical incidence. The method requires a sensitive differential photometric technique, such as that accomplished in a circular dichroism spectrometer.The refractive index of CS2 is reported in the region 260–450 mm. and the result compared to that obtained from a Kramers-Kronig integration on the 320 nm absorption band. Though this band is fairly isolated the experimentally gained result was found more reliable. This was due to difficulties in obtaining an accurate absorption coefficient of liquid CS2 as well as to the fact that the integration had to be restricted to a finite spectral range.
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| 3. |
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| 4. |
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| 5. |
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| 6. |
- Davidsson, A., et al.
(author)
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Electric Dichroism Spectroscopy
- 1977
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In: Spectroscopy Letters. - : Informa UK Limited. - 1532-2289 .- 0038-7010. ; 10:6, s. 447-454
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Journal article (peer-reviewed)abstract
- Legrand-Grosjean circular dichroism spectrometers are easily converted to detect electric dichroism (ELD), i.e. anisotropic absorption due to an external electric field. The sensitivity enables the studying of small molecules with dipole moments or anisotropic polarisabilities. The observed ELD is in part due to the orientation of the absorbing transition dipole (the orientational distribution being given by the interaction between the dipole and the electric field) but contributions due to perturbations (type Stark) may generally not be neglected. The method is predicted to become an important complement to LD studies in oriented matrix, to evaluate directions of transitions moments, but other applications are also possible. The experimental qualifications are demonstrated on two different species, nitrobenzene and Cu(II) ethylenediamine (acetylacetone)2.
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| 7. |
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| 8. |
- Davidsson, A., et al.
(author)
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Linear Dichroism of 1,4-Benzodiazepines
- 1976
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In: Spectroscopy Letters. - : Informa UK Limited. - 1532-2289 .- 0038-7010. ; 9:5, s. 301-311
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Journal article (peer-reviewed)abstract
- Linear dichroism and absorption spectra were measured for some 1,4-benzodiazepines dissolved and partially oriented in a polymer matrix. The results are discussed in terms of polarizations of the transitions in the two noninteracting benzene nuclei.
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| 9. |
- Davidsson, A., et al.
(author)
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New details in the polarized spectrum of naphthalene by means of linear dichroism studies in oriented polymer matrices
- 1974
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In: Chemical Physics Letters. - : Elsevier BV. - 0009-2614. ; 28:2, s. 221-224
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Journal article (peer-reviewed)abstract
- Linear dichroism (LD) spectra are presented for naphthalene oriented in stretched polyethylene and polypropylene matrices at 77 K and 296 K. From the calculated spectrum LD(λ)/A(λ), where A(λ) is the corrected absorbance spectrum of the sample by unpolarized light, orientational parameters are calculated and component spectra, 235–315 nm, are resolved corresponding to polarization parallel to the long (B3u = x) and the short (B2u = y) axes in the molecular plane (D2h). The orientational parameters indicate different orientational mechanisms in polyethylene and polypropylene, but the resolving procedure yields mainly identical component spectra. It is suggested that the polarization (B3u) predominating in the 245–275 nm region isdue to a B1g vibronic perturbation of the 1B2u state.
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| 10. |
- Davidsson, A., et al.
(author)
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On the problem of obtaining accurate circular dichroism. Calibration of circular dichroism spectrometers
- 1976
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In: Spectrochimica Acta - Part A: Molecular and Biomolecular Spectroscopy. - : Elsevier BV. - 1386-1425 .- 0584-8539. ; 32:4, s. 717-722
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Journal article (peer-reviewed)abstract
- It is questioned whether common circular dichroism (CD) spectrometers can be relied upon if they are calibrated at a single wavelength only. A procedure for obtaining the influence of certain instrumental parameters is described, and relations are given to correct the CD.This discussion was found relevant on examination of a particular commercial CD spectrometer for which fairly large corrections were necessary. It is suggested that the different values reported for two common CD standards may be explained by errors of the type considered, in different instruments.
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