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Current issue   Ukr. J. Phys. 2014, Vol. 59, N 3, p.336-343

    Paper

Kornienko M., Naumenko A.

Taras Shevchenko National University of Kyiv
(64, Volodymyrs’ka Str., Kyiv 01601, Ukraine)

The Vibrational Band Enhancements for Active and “Silent” Vibrations in the Raman and IR Spectra of Fullerene C60 Nanofilms

Section: Nanosystems
Language: English

Abstract: A comparison of the intensities of the vibrational bands (VB) in Raman and IR spectra for nanofilms of C60 150–250 nm in thickness and for microfilms 1–2 µm in thickness has been done. In the Raman spectra of nanofilms, the enhancement of the active bands Hg(1 ÷ 8) by 2 ÷7 times in comparison with a slight weakening of the Ag(1,2) band for microfilms has been observed. It is shown that the Raman and IR vibrations Gg,u, Hu, F1,2g, and F2u, which are inactive for icosahedral symmetry I, and the lateral spectral components of the bands Hg(1 ÷ 8) increase by 5–50 times and more. The observed phenomena is associated with the significant changes in the electro-physical properties of nanostructured media due to a weakening of the symmetry and an increase in the anharmonicity and the nonlinear interaction of vibrational modes. During the polymerization of a nanofilm by diamine (N2H4), the observed enhancement of VB decreases due to a decrease in the vibrational nonlinearity. The differences between the experimental intensities of VB and the results of quantum-chemical calculations are discussed.

Key words: nanofilm, fullerene, enhancement of vibrational bands, vibrational-electronic interaction, induction of electronic bands, nonlinear interaction of vibrational modes.