Ion Irradiation of Solid Carbons - Polyynes: Synthesis, Properties, and Applications - page 273

FIGURE 13.6 Transmittance IR spectra at room temperature of: (a) an organic
residue left over after ion irradiation of frozen benzene; (b) after ion irradiation
(7.5 10 14 200 keV Ar þ cm 2 ); and (c) after exposure to air (6 days). Spectra have
been vertically shifted for clarity. After the collection of the spectrum (a) a new
background has been taken that includes the sample itself. Thus newly formed
bands are seen as ''absorbtions''; bands seen as ''emissions'' are those progressively
destroyed.

The spectrum of another residue (at 300K) is shown in Figure 13.6(a)
from which it is possible to see again the appearance of C-H stretching
bands of the three hybridizations. The sample has been further irradiated
and the spectrum obtained is shown in Figure 13.6. As in the case of
asphaltite, after the collection of spectrum (a) a new background has been
taken that includes the sample itself. Thus newly formed bands are seen, in
the transmittance scale, as ''absorbtions''; bands seen as ''emissions'' are
those progressively destroyed. The appearance of the 3301 cm 1 and
2106 cm 1 bands testifies for the ion-induced synthesis of carbynoid
structures. According to the literature data [14], carbynoid species are
extremely reactive if exposed to air. In fact the C C band completely

disappears (see Figure 13.6c) if the sample is exposed to atmospheres for
some days. At the same time new and different C-H bands are detected due
to alterations as observed in the same spectrum.