A new mechanism of Raman enhancement and its application

Yizhuang Xu, Jinguang Wu, Wenxiu Sun, Dongliang Tao, Limin Yang, Zengfu Song, Shifu Weng, Zhenhua Xu, Roger D. Soloway, Duanfu Xu, Guangxian Xu

Research output: Contribution to journalArticlepeer-review

26 Scopus citations


Strong electronic Raman bands corresponding to the transition between 4I9/2 and 4I11/2 manifolds of Nd3+, caused by a Raman-enhancement effect, are observed in the FT-Raman spectrum of Nd2O3. Neither resonance enhancement (RR) nor surface enhancement (SERS) accounts for the Raman enhancement observed here. We propose a new mechanism of Raman enhancement called the "feed-back" mechanism. A YAG laser excites the final state of the Raman transition (4I11/2 of Nd3+) to the 4F3/2 state and causes a significant decrease in the population of Nd3+ at the 4I11/2 state. This causes the population ratio of Nd3+ at 4I9/2 and 4I11/2 to deviate from the value required by Boltzmann's law. To restore equilibrium, Raman scattering is enhanced so that more Nd3+ ions are brought from the 4I9/2 state to the 4I11/2 state. This hypothesis gets support from the temperature-variable FT-Raman spectroscopic results. Additionally, obvious differences between the Stokes and anti-Stokes Raman spectrum of Nd3+ provide further evidence to support the feed-back mechanism. The Raman-enhancement effect confers on the electronic Raman bands a special ability to reflect the variation of coordinated structure around metal ions. The structural variations in polymer-metal ion composites and biomineralization systems have been investigated by using the electronic Raman bands.

Original languageEnglish (US)
Pages (from-to)5323-5331
Number of pages9
JournalChemistry - A European Journal
Issue number23
StatePublished - Dec 2 2002


  • Analytical methods
  • Enhancement
  • Feed-back mechanism
  • Lanthanides
  • Raman spectroscopy
  • Structural probe

ASJC Scopus subject areas

  • Catalysis
  • Organic Chemistry


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