Chemistry Reference
In-Depth Information
FIGURE 14.5
Laboratory angular distribution of the m/e
¼
50 ion (C
3
N
þ
) at the
collision energies of 21.1 kJ/mol together with the corresponding Newton diagram.
The circle in the Newton diagram delimits the maximum velocity that the HCCCN
product can attain on the basis of energy conservation if all the available energy for
the corresponding channels goes into product translational energy. The TOF
spectrum of the m/e
¼
50 ion at the center-of-mass angles of 32
is also shown. The
solid lines superimposed to the experimental points are the calculated curves when
using the best-fit center-of-mass functions of
Figure 14.6
(adapted from
References
75
and
82
).
drawn assuming that all the available energy is released as product trans-
lational energy in the case that cyanoacetylene is the formed product. If we
compare this limit with the experimentally determined maximum speed of
the C
2
HN product(s), the substantial coincidence indicates that HCCCN
must be significantly formed. The two best fit values of P(E
0
T
) are charac-
terized by a maximum value of translational energy, E
TOT
, of about 100-
130 kJ/mol (note that by extending or cutting the high energy tails of the
best fit values of P(E
0
T
)by10kJmol
1
the quality of the fit does not
change significantly). Since the energy conservation rule states that E
TOT
¼
E
c
H
0
; once we account for the relative collision energies, the CN/H
Search WWH ::
Custom Search