High pressure study of phase transitions and intermolecular interaction in crystalline benzene

Gaidai, S. I.; Meletov, K. P.

doi:10.1016/0301-0104(92)87022-2

Cited by 3 publications

(4 citation statements)

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“…The dipolar approximation as a well-established theoretical approach has been routinely applied to interpret exciton spectra in molecular crystals of aromatic series, such as anthracene and tetracene. , And yet, the pressure experiments on the same series of crystals have shown that the factor group or Davydov splitting increases much stronger than expected based on not only dipolar but also multipolar terms of expansion of resonant interactions. − This has been taken as an indication of a short-range character of the intermolecular couplings. Here, we shall take a similar approach to test the electronic coupling mechanisms in the LH2 antenna protein complexes by studying their spectra under compression.…”

Section: Introductionmentioning

confidence: 99%

Short-Range Exciton Couplings in LH2 Photosynthetic Antenna Proteins Studied by High Hydrostatic Pressure Absorption Spectroscopy

et al. 2001

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The effects of high hydrostatic pressure (up to 8 kbar) on bacteriochlorophyll a Q y electronic absorption bands of LH2 photosynthetic antenna complexes have been studied at ambient temperature. A variety of samples were studied, including intact membranes and isolated complexes from wild type and mutant photosynthetic bacteria Rhodobacter sphaeroides, Rhodopseudomonas acidophila, and Rhodospirillum molischianum. The spectra of the complexes universally red shift and broaden under elastic compression, while the variations of the integrated intensity remain within the experimental uncertainty. A qualitatively different slope and variation of the slope of the pressure-induced shift is observed for the B800 and B850 absorption bands of LH2 complexes belonging to quasi-monomer and aggregated pigments, respectively. For the complexes from Rhodobacter sphaeroides, e.g., the corresponding slopes are −28 ± 2 and −65 ± 2 cm-1/kbar. The shift rate of the B800 band declines with pressure, while the opposite is observed for the B850 band. The shifts show little if any correlation with hydrogen bonds. Using simple phenomenological arguments and numerical simulations of molecular exciton spectra, it is shown that the shift of the B800 band is governed by pigment−protein interactions, while in addition to that, interpigment couplings (including long-range dipolar and short-range orbital overlap interactions) are instrumental for the B850 band shift. The compressibility of the B800 bacteriochlorophyll binding sites deduced from the B800 band shift at ambient pressure is ∼0.02 kbar-1, and it decreases nonlinearly with pressure. Inter-pigment couplings are responsible for approximately one-third of both the total ambient-pressure solvent shift of the B850 absorption band and its pressure-induced growth. A slight increase with pressure of the B850 band shift due to orbital overlap couplings is predicted.

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Section: Introductionmentioning

confidence: 99%

Short-Range Exciton Couplings in LH2 Photosynthetic Antenna Proteins Studied by High Hydrostatic Pressure Absorption Spectroscopy

et al. 2001

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“…These attributes result in benzene's fascinating chemistry toward formation of more complex molecules (including dyes and pharmaceutical compounds) and polymers. Recently − and in the past, − there has been interest in understanding the properties of benzene under high pressure and high-temperature, particularly in the spirit of inducing amorphization, dimerization, and other chemical transformations 6 of benzene to develop high-pressure methods for creating novel compounds and polymers. − Shock wave studies of benzene have also been performed − and thus understanding the behavior of this compound under static high pressure would be useful to complement data of the material under dynamic loading conditions. The techniques used to interrogate benzene under pressure have been primarily X-ray diffraction, − Raman 6,9,12 and infrared (IR) 4,8 spectroscopy, and optical absorption spectroscopy …”

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confidence: 99%

“…2 These attributes result in benzene's fascinating chemistry toward formation of more complex molecules (including dyes and pharmaceutical compounds 3 ) and polymers. Recently [3][4] and in the past, [5][6][7][8][9][10][11][12] there has been interest in understanding the properties of benzene under high pressure and high-temperature, particularly in the spirit of inducing amorphization, 4 dimerization, 5 and other chemical transformations 6 of benzene to develop high-pressure methods for creating novel compounds and polymers. [3][4] Shock wave studies of benzene have also been performed [13][14] and thus understanding the behavior of this compound under static high pressure would be useful to complement data of the material under dynamic loading conditions.…”

mentioning

confidence: 99%

“…The techniques used to interrogate benzene under pressure have been primarily X-ray diffraction, [4][5][6][7] Raman 6,9,12 and infrared (IR) 4,8 spectroscopy, and optical absorption spectroscopy. 11 It is in this spirit of better understanding the inter-and intramolecular changes to benzene at high pressure that we performed X-ray Raman spectroscopic measurements using a diamond anvil cell for pressure generation, 15 the first such measurement for benzene or any hydrocarbon that we are aware of under extreme conditions. X-ray Raman spectroscopy (XRS) 1,[16][17] is a valuable technique for probing core electron bonding where a hard X-ray (2-10 keV 1 ) inelastically scatters from core electrons while exciting them into unoccupied states.…”

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X-ray Raman Spectroscopic Study of Benzene at High Pressure

Pravica

Grubor-Urosevic

et al. 2007

J. Phys. Chem. B

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We have used X-ray Raman spectroscopy (XRS) to study benzene up to approximately 20 GPa in a diamond anvil cell at ambient temperature. The experiments were performed at the High-Pressure Collaborative Access Team's 16 ID-D undulator beamline at the Advanced Photon Source. Scanned monochromatic X-rays near 10 keV were used to probe the carbon X-ray edge near 284 eV via inelastic scattering. The diamond cell axis was oriented perpendicular to the X-ray beam axis to prevent carbon signal contamination from the diamonds. Beryllium gaskets confined the sample because of their high transmission throughput in this geometry. Spectral alterations with pressure indicate bonding changes that occur with pressure because of phase changes (liquid: phase I, II, III, and III') and possibly due to changes in the hybridization of the bonds. Changes in the XRS spectra were especially evident in the data taken when the sample was in phase III', which may be related to a rate process observed in earlier shock wave studies.

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Simulated pressure response of crystalline indole

Schatschneider

Liang²

2011

The Journal of Chemical Physics

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The isostatic pressure response of crystalline indole up to 25 GPa was investigated through static geometry optimization using Tkatchenko-Scheffler dispersion-corrected density functional theory method. Different symmetries were identified in the structural evolution with increased pressure, but no motif transition was observed, owing to the stability of the herringbone (HB) motif for small polycyclic aromatic hydrocarbons. Hirshfeld surface analysis determined that there was an increase in the fraction of H···π and π···π contacts within the high pressure structures, while the fraction of H···H contacts was lowered via geometric rearrangements. It was found that isostatic pressure alone, up to 25 GPa, was not sufficient to induce a chemical reaction due to the poor π-orbital overlap existing within the HB motif. However, the applied pressure sets the stage for an activated chemical reaction when the molecules approach each other along the long molecular axis, with a reaction energy and reaction barrier of 1.05 eV and 1.80 eV per molecular unit, respectively.

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High pressure study of phase transitions and intermolecular interaction in crystalline benzene

Cited by 3 publications

References 13 publications

Short-Range Exciton Couplings in LH2 Photosynthetic Antenna Proteins Studied by High Hydrostatic Pressure Absorption Spectroscopy

Short-Range Exciton Couplings in LH2 Photosynthetic Antenna Proteins Studied by High Hydrostatic Pressure Absorption Spectroscopy

X-ray Raman Spectroscopic Study of Benzene at High Pressure

Simulated pressure response of crystalline indole

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