POLARIZED FTIR - SPECTRA OF C-60 LAYERS AND THE ADSORBATES OF CO AND CO2 ON C-60

Thin films of buckminsterfullerene C-60 were deposited on KBr(100) at 78 K that were prepared by cleaving in UHV. The thickness of the film was monitored by recording the IR spectrum of C-60 at different polari zations. For the first time FTIR spectra of CO and CO2 adsorbed on C-6 0 film were measured under UHV conditions. At pressures < 10(-9) mbar the transmission spectra of CO2 adsorbed on the C-60 film at temperatu res below 90 K show a single v(3) absorption peak at 2328 cm(-1) with a linewidth (FWHM) of 5 cm(-1). At higher CO2 pressures the coverage g rows and the linewidth and intensity of the absorption peak increase. A second absorption peak at 2331+/-1 cm(-1) was detected. At still hig her pressures multilayer adsorption takes place with absorptions at 23 44 and 23 80 cm(-1) at p-polarization and 2344 cm(-1) at s-polarizatio n. A single absorption peak of CO adsorbed on C-60 was recorded in tra nsmission at 2134 cm(-1) with a linewidth of 5 cm(-1) at temperatures below 40 K. With increasing CO pressure a peak shift to 2138 cm(-1) an d an enhancement of the linewidth to 10 cm(-1) was observed. Still hig her pressures lead to multilayer adsorption with absorptions at 2142 a nd 2139 cm(-1) at p-polarization and 2139 cm(-1) at s-polarization. Al l absorptions detected, including the C-60 spectra, possess higher int ensities at s-polarization than at p-polarization. At an angle of inci dence of 45 degrees the ratio of the integrated absorption (A(s)/A(P)) at s-polarization and p-polarization respectively is 1.3.