Abstract
The resonant Raman scattering of C60 crystallites is monitored as a function of excitation intensity at 514.5 nm. At low intensities, a strong line at 1468 cm−1 is observed. No feature at 1459 cm−1 is observable. With increasing intensities, the 1468 cm−1 line shifts continuously and reversibly to lower frequencies. The mode softening is nonlinearly dependent on the input intensity and is accompanied by a nonlinear increase in the Raman intensity. The spectral changes are discussed in terms of a nonlinear reduction in force constant and increase in bond polarisability as a result of an increased intermolecular delocalisation of the π-electron cloud. The nonlinear changes are associated with the nonlinear luminescence and photoconductive response observed in fullerenes and are contrasted to the irreversible phototransformation recently discussed.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
H.W. Kroto, J.R. Heath, S.C. O'Brien, R.F. Curl, R.E. Smalley: Nature 318, 162 (1985)
W. Krätschmer, L.D. Lamb, K. Fostiropoulus, D.R. Huffman: Nature 347, 354 (1990)
P.A. Lane, L.S. Swanson, Q.-X. Ni, J. Shinar, J.P. Engel, T.J. Barton, L. Jones: Phys. Rev. Lett. 68, 887 (1992)
H.J. Byrne, W.K. Maser, W.W. Rühle, A. Mittelbach, S. Roth: Appl. Phys. A 56, 235 (1993)
H.J. Byrne, W.K. Maser, M. Kaiser, L. Akselrod, W.W. Rühle, X.-Q. Zhou, A. Mittelbach, S. Roth: Appl. Phys. A 57, 81 (1993)
D.S. Bethune, G. Meijer, W.C. Tang, H.J. Rosen, W.G. Golden, H. Seki, C.A. Brown, M.S. de Vries: Chem. Phys. Lett. 179, 181 (1991)
P. Zhou, A.M. Rao, K.-A. Wang, J.D. Robertson, C. Eloi, M.S. Meier, S.L. Ren, X.-X. Bi, P.C. Eklund: Appl. Phys. Lett. 60, 2871 (1992)
M. Matus, H. Kuzmany: Appl. Phys. A 56, 241 (1992)
P.H.M. van Loosdrecht, P.J.M. van Bentum, G. Meijer: Chem. Phys. Lett. 205, 191 (1993)
A. Mittelbach, W. Hönle, H.G. von Schnering, J. Carlsen, R. Janiak, H. Quast: Angew. Chem. 104, 1681 (1992)
M.A. Verheijen, H. Meekes, G. Meijer, E. Raas, P. Bennema: Chem. Phys. Lett. 191, 339 (1992)
L. Akselrod, H.J. Byme, C. Thomsen, A. Mittelbach, S. Roth: Chem. Phys. Lett. (1993) to be published
D.W. Snoke, M. Cardona: Solid State Commun. (1993), to be published
P.C. Eklund: Proc. of the Int'l Winterschool on the Electronic Properties of Novel Materials, Austria, March 1993, Springer Ser. Solid-State Sci., Vol. 117 (Springer, Berlin, Heidelberg 1993)
See for example Physics of Highly Excited States in Solids, ed. by M. Ueta, Y. Nishina, Lecture Notes Physics, Vol. 57 (Springer, Berlin, Heidelberg 1976)
C.D. Jeffries, L.V. Keldish (eds.): Electron-Hole Droplets in Semiconductors (North-Holland, Amsterdam 1983)
H.J. Byrne, W.K. Maser, M. Kaiser, W.W. Rühle, L. Akselrod, A.T. Werner, J. Anders, X.-Q. Zhou, G. Mahler, T. Kuhn, A. Mittelbach, S. Roth: Appl. Phys. A 57, 303 (1993)