Emission of the CO Fourth Positive Bands (A 1π–X 1Σ+) is observed in the reactions of atomic N/O mixtures with C2F4, C2H4, C2H2, and C2N2 at about 300°K and pressures of 1–4 Torr. The N/O/C2F4 system, which has been investigated most extensively, produces CO A 1π–X 1Σ+ emission which, like the NO+ chemi‐ion formation rate, follows [N]3[O] kinetics. The level of excitation extends to at least 10.3 eV above CO(X 1Σ+, υ = 0). It is shown that the formation of CO(A 1π) can be attributed to enhanced formation of excited N2 and NO molecules in atom‐recombination reactions induced by a reaction intermediate (probably CN), followed by pooling of the energy of an N2* and an NO* molecule and energy transfer to the reaction product CO(X 1Σ+). The transfer reaction can take place before or after the pooling reaction. Formation of CO(A 1π) in the N/O/C2H4 system exhibits the same kinetic dependence on N and O atoms. For the N/O/C2H2 system, the observations indicate CO(A 1π) formation both via the above energy‐pooling mechanism and via the mechanism operative in the O/C2H2 reaction [O+C2O→CO(A1π)+CO(X1Σ+)]. In the N/O/C reactions, the higher vibrational levels of CO(A 1π) are relatively more populated than in the O/C2H2 reaction.

1.
A. Fontijn and P. H. Vree, Symp. Combust. 11th, Berkeley, Calif., 1966, 343 (1967);
J. Phys. Chem.
70
,
2071
(
1966
).
2.
A. Fontijn (unpublished results).
3.
C. A.
Arrington
,
O. O.
Bernardini
, and
G. B.
Kistiakowsky
,
Proc. Roy. Soc. (London)
A310
,
161
(
1969
).
4.
A.
Fontijn
and
R.
Ellison
,
J. Phys. Chem.
72
,
3701
(
1968
).
5.
L. F.
Phillips
,
Can. J. Chem.
46
,
1450
(
1968
).
6.
A.
Fontijn
and
G. L.
Baughman
,
J. Chem. Phys.
38
,
1784
(
1963
).
7.
A. Fontijn, “Chemi‐ionization Reactions in the Gas Phase,” Progr. Reaction Kinetics (to be published).
8.
K. H.
Becker
and
K. D.
Bayes
,
J. Chem. Phys.
48
,
653
(
1968
);
K. H.
Becker
and
K. D.
Bayes
,
45
,
396
(
1966
).,
J. Chem. Phys.
9.
F. F.
Marmo
,
J. P.
Padur
, and
P.
Warneck
,
J. Chem. Phys.
47
,
1438
(
1967
).
10.
J. A. R. Samson, Techniques of Vacuum Ultraviolet Spectroscopy (Wiley, New York, 1967), p. 244ff.
11.
I. M.
Campbell
and
B. A.
Thrush
,
Trans. Faraday Soc.
65
,
32
(
1969
).
12.
P. H.
Krupenie
,
Natl. Std. Ref. Data Ser. Natl. Bur. Std. (U.S.)
5
(
1966
).
13.
The subscript “0” denotes concentration before reaction.
14.
The apparent absence of CO 4+ emission in the O/C2H4 reaction is consistent with the commonly accepted mechanism8,9 for this emission in hydrocarbon flames and the O/C2H2 reaction, i.e., O+C2OCO(A 1Π)+CO(X 1Σ+). The intermediate species C2O is not expected to form in the early stages of the O/C2H4 reaction observed in the present work.
15.
C. R.
Gatz
,
F. T.
Smith
, and
H.
Wise
,
J. Chem. Phys.
40
,
3743
(
1964
).
16.
J. E.
Hesser
,
J. Chem. Phys.
48
,
2518
(
1968
).
17.
W. C.
Wells
and
R. C.
Isler
,
Phys. Rev. Letters
24
,
705
(
1970
).
18.
If the Σ5g+ state is in equilibrium with free ground state atoms [cf.
S. W.
Benson
,
J. Chem. Phys.
48
,
1765
(
1968
)], then its concentration cannot be enhanced by C2F4, etc., addition which makes it unlikely that this state contributes in any important manner to CO(A 1Π) formation.
19.
For a discussion of these N2 states, see A. N. Wright and C. A. Winkler, Active Nitrogen (Academic, New York, 1968), Chap. 3.
20.
For the N2 and NO potential energy diagrams, see
F. R.
Gilmore
,
J. Quant. Spectry. Radiative Transfer
5
,
369
(
1965
).
21.
J.
Heicklen
and
N.
Cohen
,
Advan. Photochem.
5
,
157
(
1968
).
22.
E. H.
Fink
and
K. H.
Welge
,
Z. Naturforsch.
23a
,
358
(
1968
).
23.
R. S.
Freund
,
J. Chem. Phys.
50
,
3734
(
1969
).
24.
Scheme II also suggests chemi‐ion production paths in N/O/C systems which are alternate to Reaction (1), e.g., the spin‐allowed reaction CO(a 3Π)+NO(a 4Π)→CO(X 1Σ+)+NO+(X 1Σ+)+e.
25.
T.
Iwai
,
D. W.
Pratt
, and
H. P.
Broida
,
J. Chem. Phys.
49
,
919
(
1968
).
26.
A.
Fontijn
,
J. Chem. Phys.
43
,
1829
(
1965
).
27.
D. R.
Safrany
and
W.
Jaster
,
J. Phys. Chem.
72
,
3318
(
1968
).
28.
R. A.
Young
,
G.
Black
, and
T. G.
Slanger
,
J. Chem. Phys.
50
,
303
(
1969
).
29.
I. M.
Campbell
and
B. A.
Thrush
,
Trans. Faraday Soc.
62
,
3366
(
1966
);
I. M.
Campbell
and
B. A.
Thrush
,
64
,
1275
(
1968
).,
Trans. Faraday Soc.
30.
N2(A 3Σu+) is used in the present calculations because quenching data are available for this metastable state. The choice of this state does not imply that we should necessarily identify it with N2*. As a matter of fact, atom‐atom interchange reactions rapidly remove A state molecules in the υ = 0 and 1 levels, thereby resulting in a steady‐state concentration proportional to [N] rather than [N]2 as required for [N2*] here. [See, e.g.,
R. A.
Young
and
G. A.
St. John
,
J. Chem. Phys.
48
,
895
(
1968
),
and
C. H.
Dugan
,
J. Chem. Phys.
47
,
1512
(
1967
)].
However, for υ⩾7 levels of the A state, atom‐atom interchange appears to be a slow process and as a result the concentration of molecules in these states could be proportional to [N]2. [See
M. P.
Weinreb
and
G. G.
Mannella
,
J. Chem. Phys.
50
,
3129
(
1969
),
M. P.
Weinreb
and
G. G.
Mannella
, and
51
,
4973
(
1969
)].,
J. Chem. Phys.
31.
D. E.
Paul
and
F. W.
Dalby
,
J. Chem. Phys.
37
,
592
(
1962
).
32.
N.
Basco
,
Proc. Roy. Soc. (London)
A283
,
302
(
1965
).
33.
L. F.
Phillips
and
H. I.
Schiff
,
J. Chem. Phys.
36
,
1509
(
1962
).
34.
D. H.
Stedman
and
D. W.
Setser
,
J. Chem. Phys.
50
,
2256
(
1969
).
35.
R. E.
Lund
and
H. J.
Oskam
,
Z. Physik
219
,
131
(
1969
);
R. E.
Lund
and
H. J.
Oskam
,
J. Chem. Phys.
48
,
109
(
1968
).
36.
E. A.
Ogryzlo
and
A. E.
Pearson
,
J. Phys. Chem.
72
,
2913
(
1968
).
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