Exciton—phonon coupling and pressure-induced structural phase changes in coronene crystals

Yamamoto, Takahiro; Nakatani, Shigeru; Nakamura, Tadashi; Mizuno, Ken-ichi; Matsui, Atsuo; Akahama, Yuichi; Kawamura, Haruki

doi:10.1016/0301-0104(94)00084-0

Cited by 21 publications

(34 citation statements)

References 26 publications

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“…Single-crystal flakes were grown by sublimation in nitrogen atmosphere. Details of purification processes and crystal growth techniques are described elsewhere [5]. The crystal was mounted on a substrate which was made of glass coated with tin oxide (transparent electrodes).…”

Section: Methodsmentioning

confidence: 99%

“…where I is the transmitted light intensity, T temperature, n refractive index, dN=do the density of states, F oscillator strength, t the thickness of the sample, and the other symbols have their usual meaning [5]. If one assumes that F and m are independent of the crystal momentum K, and T, DT and t are taken to be constant during a measurement, Eq.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Density of states of the lowest exciton band and the exciton bandwidth in coronene single crystals

Totoki

Aoki-Matsumoto

Mizuno

2005

Journal of Luminescence

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Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Density of states of the lowest exciton band and the exciton bandwidth in coronene single crystals

Totoki

Aoki-Matsumoto

Mizuno

2005

Journal of Luminescence

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“…For phase II, all the diffraction peaks were resolved at 2.2 GPa and indexed mainly to the mon-oclinic system or orthorhombic system. Compared to the similar organic compound coronene 42 , investigations reveled that coronene transformed to the body centered orthorhombic structure from monoclinic phase below 2.0 GPa. However, the orthorhombic phase group is not suitable in our cases because of the bad fitting results.…”

Section: B Analysis Of Structural Evolution With Pressurementioning

confidence: 99%

Structural and vibrational properties of phenanthrene under pressure

Huang

Zhang

Berlie

et al. 2013

The Journal of Chemical Physics

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The structural and vibrational properties of phenanthrene are measured at high pressures up to 30.2 GPa by Raman spectroscopy and synchrotron x-ray diffraction techniques. Two phase transitions are observed in raman spectra under pressures of 2.3 GPa and 5.4 GPa with significant changes of intermolecular and intramolecular vibrational modes, and all the raman peaks disappeared in the luminesce background above 10.2 GPa. Upon further compression above 20.0 GPa, three broad bands are observed respectively around 1600, 2993 and 3181 cm −1 in Raman spectra, strongly indicating that phenanthrene has transformed into amorphous hydrogenated carbon. Based on x-ray diffraction, the structures of corresponding phases observed in Raman spectra are identified with space group of P21 for phase I at 0-2.2 GPa, P2/m for phase II at 2.2-5.6 GPa and P2/m+Pmmm for phase III at 5.6-11.4 GPa , and the structure above 11.4 GPa is identified with space group of Pmmm. Although phenanthrene has amorphized above 20.0 GPa, the amorphous hydrogenated carbon clusters still remain the crystalline characteristic based on x-ray diffraction patterns. Our results suggest that the long-range periodicity and the local disorder state coexist in phenanthrene at high pressures.

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“…The pressure-induced transitions in coronene from monoclinic to orthorhombic structure were suggested at 1 GPa [22], whereas Fourier transform infrared spectroscopy experiments revealed a phase transition between 2.0 and 3.2 GPa [23]. In a recent work, Zhao et al [24] argued for a transition from P2 1 /a to P2/m at 1.5 GPa and to Pmmm at 12.2 GPa.…”

Section: Introductionmentioning

confidence: 95%

Thermal expansion of coronene C24H12 at 185–416 K

Litasov

Gavryushkin

Yunoshev

et al. 2014

J Therm Anal Calorim

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The coefficient of the thermal expansion of P2 1 /a coronene was measured using X-ray diffraction in the temperature range from 185 to 416 K. It increases with increasing temperature from 4.8 9 10 -5 K -1 at 185 K to 4.9 9 10 -4 K -1 at 416 K. At 298 K, a = 1.9 9 10 -4 K -1 . In the temperature interval between 298 and 416 K, the thermal expansion can be described by equation a = -6.66 9 10 -4 ? 2.72 9 10 -6 T ? 4.62 T -2 . Comparison with previous data indicates that the thermal expansion of PAHs decreases with an increasing amount of benzene rings in their structure.

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Exciton—phonon coupling and pressure-induced structural phase changes in coronene crystals

Cited by 21 publications

References 26 publications

Density of states of the lowest exciton band and the exciton bandwidth in coronene single crystals

Density of states of the lowest exciton band and the exciton bandwidth in coronene single crystals

Structural and vibrational properties of phenanthrene under pressure

Thermal expansion of coronene C24H12 at 185–416 K

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