Pressure‐induced Fermi resonance between fundamental modes in 7,7,8,8‐tetracyanoquinodimethane

Sun, Chia‐Chung; Hong-liang, Zhao; Liu, Chunyu; Zhou, Mi

doi:10.1002/jrs.5191

Cited by 12 publications

(4 citation statements)

References 34 publications

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“…The linear increase of the values of Δ, Δ 0 and R in Figure S8 reflect the decoupling trend of FR from 1 atm to 2.1 GPa caused by wavenumber separation. [46,47] Because the magnitude of W is dependent on the degree of vibrational anharmonicity, the increase of W below 2.1 GPa could be explained as the enhancement of weak hydrogen bonds in PA crystal, which leads to the N-H sym str become more anharmonic. [48] When the pressure reaches 3.5 GPa, the N-H sym str mode suddenly broadens, resulting a greater overlap with the combination tone.…”

Section: Resultsmentioning

confidence: 99%

High‐pressure‐induced multiple phase transitions of parabanic acid

Duan

Dai

et al. 2023

J Raman Spectroscopy

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In situ high‐pressure Raman spectroscopy experiments have been performed to investigate the structural changes of parabanic acid (PA) up to ~12.0 GPa. The analysis of Raman spectroscopy reveals that PA undergoes two phase transitions. The collapse of spacing between molecular layers and the distortion of hydrogen‐bonding networks almost in ac‐plane are the main causes of the first phase transition above 2.1 GPa. The changes of Fermi resonance parameters also provide evidence for the first phase transitions. The second phase transition around 4.0 GPa can attribute to the further reduction of the molecular interlayer spacing and the resulting distortion of hydrogen‐bonding network. First‐principle calculations and Hirshfeld surfaces further confirm the analysis of the experimental results. The analysis of high‐pressure phase transition contributes a better explanation for the high‐pressure phase transition process of layered supramolecular materials with hydrogen‐bond self‐assembly. This study provides the possibility of two new polymorphs for PA under high pressure and is helpful for broadening its potential application of this material, especially in the field of supramolecular chemistry.

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Section: Resultsmentioning

confidence: 99%

High‐pressure‐induced multiple phase transitions of parabanic acid

Duan

Dai

et al. 2023

J Raman Spectroscopy

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“…In general, due to the requirement of similar frequency and same symmetry of vibrational modes, Fermi resonance, usually occurs between a fundamental mode and a combination or overtone mode, is rarely observed between fundamental vibrational modes. Recently, with the application of high-pressure techniques, materials' crystal and electronic structures can be tuned efficiently by external compression thus result in a modification of symmetry and frequency in vibrational modes, which makes the coupling between fundamental modes becomes possible [19,20]. Pressure is a powerful method which can effectively change the symmetry of molecular crystal and the frequencies of vibrational modes, thus provides more chances to the coupling between adjacent vibrational modes (Fermi resonance).…”

Section: Raman Spectra Of Pa At High Pressurementioning

confidence: 99%

“…In addition, a double Fermi resonance has been proposed in hexachloroethane [18]. Furthermore, a pressure-induced Fermi resonance between fundamental modes were reported in tetramethylurea and 7,7,8,8-tetracyanoquinodimethane [19,20], where an exponential relationship between Raman intensity ratio to pressure was proposed. In the latest study, a Fermi resonance between the lowest frequency Ag symmetry peaks (ν4 and ν5) between ∼10 and ∼30 GPa has been observed in ilmenite [21].…”

Section: Introductionmentioning

confidence: 98%

Pressure-induced Fermi resonance between fundamental modes in phthalic anhydride

Liu

Chen

Liu

et al. 2022

J. Phys.: Condens. Matter

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In-situ high-pressure Raman spectra of phthalic anhydride (PA) have been measured up to 16 GPa through diamond anvil cell (DAC) technique. The results show that all the Raman bands are blue-shifted with the increase of pressure, accompanied by appearance of some new bands. A Fermi resonance phenomenon of the two Raman fundamental modes of PA at 773 cm-1 and 801 cm-1 is proposed at pressures above 6.6 GPa, where a possible first-order phase transition occurs. The pressure-induced changes of Fermi resonance parameters, e.g., intensity ratio, coupling coefficient and frequency gap of unperturbed transition, are discussed.

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“…The relationship of Fermi resonance parameters (intensity ratio, coupling coefficient, frequency separation, and frequency separation of unperturbed transitions) with pressure was discussed. The frequency separation dominated the decay of the intensity ratio of Fermi resonance doublets, and this is another characteristic of anharmonic coupling between fundamental modes . Tribaudino et al described the high‐pressure Raman spectroscopy of Ca (Mg,Co)Si 2 O 6 and Ca (Mg,Co)Ge 2 O 6 clinopyroxenes.…”

Section: High Pressure and Temperature Studiesmentioning

confidence: 99%

Recent advances in linear and nonlinear Raman spectroscopy. Part XII

Nafie

2018

J Raman Spectroscopy

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This annual review is an overview of advances in the field of Raman spectroscopy as found in papers published in the previous calendar year in the Journal of Raman Spectroscopy (JRS), as well as in trends over the past decade across journals that have published papers important to the field of Raman spectroscopy. This information is gleaned from statistical data on article counts obtained from the Clarivate Analytic's Web of Science Core Collection by year and by subfield of Raman spectroscopy. Additional information is gleaned from presentations at the XXVI International Conference on Raman Spectroscopy (ICORS 2018) in Jeju Island, Korea in August 2018, and contributions on Raman scattering at SCIX 2018, organized by the Federation of Analytical Chemistry and Spectroscopy Societies (FACSS) in Atlanta, Georgia, USA in October 2018. Coverage is also provided for topics from the European Conference on Nonlinear Optical Spetroscopy (ECONOS 2018) held in April in Milan, Italy and GeoRaman 2018 in Catania, Italy in June. Finally, papers published in JRS in 2017 are highlighted and arranged by topics at the frontier of Raman spectroscopy. On the basis of this survey information, it is clear that Raman spectroscopy continues as in recent years as a rapidly expanding field of research across a wide range of novel disciplines and applications that provide sensitive photonic information of matter at the molecular level.

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Pressure‐induced Fermi resonance between fundamental modes in 7,7,8,8‐tetracyanoquinodimethane

Cited by 12 publications

References 34 publications

High‐pressure‐induced multiple phase transitions of parabanic acid

High‐pressure‐induced multiple phase transitions of parabanic acid

Pressure-induced Fermi resonance between fundamental modes in phthalic anhydride

Recent advances in linear and nonlinear Raman spectroscopy. Part XII

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