Pressure-induced Fermi resonance between fundamental modes in phthalic anhydride

HaiRui Liu; YinQi Chen; Guangtao Liu; Mi Zhou

doi:10.1088/1361-648X/ac577c

Pressure-induced Fermi resonance between fundamental modes in phthalic anhydride

J Phys Condens Matter. 2022 Mar 10;34(20). doi: 10.1088/1361-648X/ac577c.

Authors

HaiRui Liu¹, YinQi Chen¹, Guangtao Liu¹, Mi Zhou¹

Affiliation

¹ College of physics, Jilin University, Changchun, 130012, People's Republic of China.

PMID: 35193125
DOI: 10.1088/1361-648X/ac577c

Abstract

In situhigh-pressure Raman spectra of phthalic anhydride (PA) have been measured up to 16 GPa through diamond anvil cell 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^-1and 801 cm^-1is 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.

Keywords: Fermi resonance; phthalic anhydride; pressure.