LATTICE-DYNAMICS AND HYPERFINE INTERACTIONS OF C60FE(CO)(4)

Detailed Fe-57 Mossbauer experiments over the range 85<T<210 K have be en carried out on the tetra-carbonyl iron derivative of C-60(I) as wel l as on several related organometallic solids. The observed isomer shi ft and quadrupole splitting parameters are consistent with a bonding i nteraction between the metal center and the ligand which involves a si ngle carbon-carbon double bond of the buckminsterfullerene. The temper ature dependence of the recoil-free fraction, compared to analogous da ta for maleic anhydride Fe(CO)(4)(II), suggests that the two previousl y observed low frequency lattice modes in C-60 persist in I. Contrary to expectations, there is no significant temperature-dependent vibrati onal anisotropy (Gol'danskii-Karyagin effect) evident in the above tem perature range. (C) 1996 American Institute of Physics.