title: Unusual Raman spectra of para-nitroaniline by sequential Fermi resonances.
abstract: In this communication, we report the unusual Raman spectra of para-nitroaniline (PNA) by sequential Fermi resonances. The combinational mode 1292 cm(-1) in the experimental Raman spectrum indirectly gains the initial spectral weight at 1392 cm(-1) by three sequential Fermi resonances. These Fermi resonances result in the strong interaction between the donor group of NH2 and the acceptor group of NO2. Our theoretical calculations provide reasonable interpretation for the abnormal Raman spectra of PNA. Experimental surface enhanced Raman scattering (SERS) spectrum of PNA further confirmed our conclusion, where the strongest Raman peak at 1292 cm(-1) is very weak, while the Raman peak at 1392 cm(-1) becoming the strongest Raman peak, which is consistent with the theoretical simulations.
authors.affiliation: Department of Chemistry and Physics, Liaoning University, Shenyang 110036, PR China; School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100, PR China.
authors.forename: Jiarui
authors.initials: J
authors.lastname: Xia
authors.affiliation: National Center for Nanoscience and Technology, Beijing 100190, PR China.
authors.forename: Ling
authors.initials: L
authors.lastname: Zhu
authors.affiliation: Department of Chemistry and Physics, Liaoning University, Shenyang 110036, PR China.
authors.forename: Yanting
authors.initials: Y
authors.lastname: Feng
authors.affiliation: Department of Chemistry and Physics, Liaoning University, Shenyang 110036, PR China.
authors.forename: Yongqing
authors.initials: Y
authors.lastname: Li
authors.affiliation: Leibniz Institute of Photonic Technology, Albert-Einstein-Str. 9, 07745 Jena, Germany; Physical Chemistry, Friedrich-Schiller University Jena, Helmholtzweg, 07743 Jena, Germany. Electronic address: Zhenglong.Zhang@ipht-jena.de.
authors.forename: Zhenglong
authors.initials: Z
authors.lastname: Zhang
authors.affiliation: Department of Chemistry and Physics, Liaoning University, Shenyang 110036, PR China. Electronic address: lixinxia@lnu.edu.cn.
authors.forename: Lixin
authors.initials: L
authors.lastname: Xia
authors.affiliation: Key Laboratory of Nanodevices and Applications, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou, Jiangsu 215123, PR China.
authors.forename: Liwei
authors.initials: L
authors.lastname: Liu
authors.affiliation: Department of Chemistry and Physics, Liaoning University, Shenyang 110036, PR China.
authors.forename: Fengcai
authors.initials: F
authors.lastname: Ma
mesh_terms: D000814:Aniline Compounds / Q000737:chemistry*; D008958:Models, Molecular; D009585:Nitrogen Dioxide / Q000737:chemistry; D013059:Spectrum Analysis, Raman / Q000379:methods
chemical_list: D000814:Aniline Compounds; C019498:4-nitroaniline; D009585:Nitrogen Dioxide
keywords: Absorption spectroscopy; Acceptor group; Donor group; Fermi resonances; Para-nitroaniline; Unusual Raman spectra