Frank-Condon approach for optical absorption and resonance Raman scattering in<i>trans</i>-polyacetylene

Kuzmany, H.; Imhoff, Eugene A.; Fitchen, D. B.; Sarhangi, A.

doi:10.1103/physrevb.26.7109

Cited by 80 publications

(30 citation statements)

References 17 publications

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“…The results of Peo et al [17] show indeed this increase of the background and very recent measurements of 13C NMR reported by Clarke et al [46] revealed some trans-like XMR signal even after weak doping. Raman scattering is on the other hand particularly sensitive to the disturbed areas since the lack of the POSsibility for an electron-hole pair to decay into a soliton-antisoliton pair in the short segments retains a sharper resonance as compared to the resonance of the long segments [33]. 13C NMR spectra taken a t doping concentrations above 7% are in agreement with complete isomerization of the material and thus also in agreement with the Raman results.…”

Section: Discussion Of Experimental Resultssupporting

confidence: 80%

“…This line was observed to show no dispersion and no resonance enhancement if the scattering intensity is properly corrected for absorption and reflexion [33]. However, its scattering intensity increases with sample quality.…”

Section: Discussion Of Experimental Resultsmentioning

confidence: 92%

“…The three strong lines a t 914, 1250, and 1544 cm-' in A are well known as resonance enhanced Raman scattering from vibrations in the cis-isomer [11, 20, 211, whereas the broad features around 1100 and 1500 cm-l are resonance enhanced lines from vibrations in the trans-isomer. The trans-contamination was recently shown to be in a highly disordered state [22]. Comparing traces B and C it can be seen that the intensities of the trans-lines have considerably increased upon the thermal isomerization process whereas hardly any increase of these lines after doping occurs.…”

Section: Resultsmentioning

confidence: 94%

“…I n the highly crystalline areas of the polymer obviously much more carbons can be isomerized by one dopand, whereas in the highly disturbed areas less specific doping-induced isomerization is expected. However, these bad areas are generally expected to exhibit mainly trans-geometry already after the first warming up of the polymer [22].…”

Section: Discussion Of Experimental Resultsmentioning

confidence: 99%

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Isomerization and Disorder of Polyacetylene Induced by Doping

Schügerl

Kuzmany

1982

Physica Status Solidi (b)

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Raman scattering experiments are reported for cis-(CH), and cis-(CD), doped with AsF, in a concentration range between 3 and 13%. The typical cis-lines in the spectrum decreased with increasing doping concentration until they disappear completely at around 8%. Simultaneously the non-resonant trans-line a t 1291 cm-l is observed to increase and a special high-frequency mode develops around 1590 cm-l. From the experimental results it is shown that the generation of disorder and isomerization by doping is a general phenomenon. A strong increase of the scattering cross-section observed for red laser light for the heavily doped material is correlated to a band gap closure.Es wird iiber Raman-Experimente an cis-(CH), und cis-(CD), mit AsF,-Dotierung zwischen 3 und 13% berichtet. Die Linien typisch fur cis-(CH), nehmen mit zunehmender Dotierungskonzentration ab bis sie um etwa 8% vollig verschwinden. Gleichzeitig steigt die Intensitit der nicht resonanten trans-Linie bei 1291 cm-l an, und eine spezielle hochfrequente Mode urn 1590 cm-' taucht auf. Bus diesen Ergebnissen wird gezeigt, daB Dotierung generell eine Kristallstorung und eine Isomerisation bewirkt. Eine beobachtete starke Zunahme des Streuquerschnittes fur rotes Laserlicht im stark dotierten Material wird mit einer SchlieBung der Bandlucke in Zusammenhang gebracht.

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Section: Discussion Of Experimental Resultssupporting

confidence: 80%

Section: Discussion Of Experimental Resultsmentioning

confidence: 92%

Section: Resultsmentioning

confidence: 94%

Section: Discussion Of Experimental Resultsmentioning

confidence: 99%

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Isomerization and Disorder of Polyacetylene Induced by Doping

Schügerl

Kuzmany

1982

Physica Status Solidi (b)

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“…9). About 10% short chains of around five double bonds possibly corresponding t o amorphous regions and longer chains around 40 double bonds were assumed [70]. Recent neutron diffraction measurements by Riekel et al [71] indicate chain lengths in the abundant crystalline regions of about 50 double bonds.…”

mentioning

confidence: 98%