S. N. Kolesnik

High-resolution spectroscopy of matrix-isolated fullerene molecules

Abstract We have offered a method of obtaining fine-structured vibronic spectra of fullerenes. At liquid-helium temperatures tens of narrow lines with half-width ≈ 0.5 me V have been observed in the emission and absorption spectra of fullerene molecules embedded in the matrices of some organic crystals. Using this method, the Zeeman effect on the C 70 molecules has been observed for the first time.

Optical spectroscopy of matrix-isolated halogenated fullerenes

We have undertaken to investigate optical absorption spectra of matrix-isolated halogenofullerene molecules C60Cl6, C60Cl24, and C60Br24 in the visible and near-IR regions of the spectrum. The results for C60Cl24 presented here, show that this molecule possesses a rich well-structured spectrum. The analysis of the spectrum allows to suggest a tentative scheme of the electron energy levels of C60Cl24 molecule in the region of its HOMO-LUMO gap. The optimized geometry of C60Cl24 and its charge distribution calculated at the AM1 level are also presented. The Shpol’skii effect in the absorption spectrum of C60Cl24 molecules embedded in crystalline toluene was clearly detected, in agreement with our theoretical investigation of the geometrical structure of C60Cl24 centers in toluene crystals.

Generalized symmetry and vibrational states in halogene - fullerene compounds

Abstract We present an experimental and theoretical study of phonon subsystem of different fullerites and halogene-fullerenes such as: C 60 , C 70 , C 60 I 4−x , C 70 I 2 , C 60 Vr 24 , and C 70 Cl x . Two types of chemical bonding in these materials have been established: (i) C 60 I 4−x and C 70 I 2 compounds are formed by C 60 or C 70 molecule sublattice, and I 2 molecule sublattice which weakly interact via van-der-Waals forces; (ii) C 60 Br 24 , C 60 Cl 24 , and C 70 Cl 17 compounds are characterized by a strong covalent bonding CBr, CCl. In C 60 Cl 24 , we discovered the effect of resonance Raman scattering. This effect is attributed to interaction of phonon subsystem and electron states with energies 2.3 – 2.5 eV.

Narrow-line spectra of fullerene molecules in a crystalline matrix

The new allotropic form of carbon, the fullerenes, which possess unusual physical properties and are promising for various practical applications, have received much attention in recent years. Revealing the energy structure of fullerenes is one of the pressing problems of the physics of these novel materials. Rich information on their electronic and vibrational states could be obtained from optical spectra. However, until recently only wide-band absorption and emission spectra of fullerenes were observed in both solutions and the crystalline state (in fullerites), which did not allow full advantage of to be taken optical spectroscopy. The possibility of producing narrow-line spectra of fullerene C{sub 70} molecules in solid solutions of organic crystals at low temperatures was established. The present paper contains more detailed information on these spectra. In addition, observation of the narrow-line spectrum of the fullerene C{sub 60} molecule is reported for the first time. First the authors consider C{sub 70} spectra.

Phonon symmetry and Raman spectra of fullerites

Abstract A group-theory analysis of phonon symmetries in C 60 : I 4 crystals is performed. The Raman spectra of various fullerites and shungites are investigated.