The photodissociation spectroscopy and dynamics of the HNCN free radical have been investigated by fast beam photofragment translational spectroscopy. Predissociative transitions for both the B̃ 2A←X̃ 2A band and a higher-energy band system assigned to the C̃ 2A←X̃ 2A band were observed. Photofragment mass distributions indicate that N2 loss is the primary dissociation pathway. Translational energy distributions reveal a resolved vibrational structure of the N2 fragment, suggesting that the HNCN radical first isomerizes to a cyclic HCN2 intermediate. A dissociation mechanism is proposed in which electronically excited HNCN undergoes internal conversion to the ground state, followed by isomerization to cyclic HCN2 and dissociation through a tight three-center transition state. The HNCN bond dissociation energy D0 and heat of formation ΔfH0(HNCN) were determined to be 2.80±0.03 eV and 3.35±0.03 eV, respectively.

1.
J. A.
Miller
and
C. T.
Bowman
,
Prog. Energy Combust. Sci.
15
,
287
(
1989
).
2.
J. A.
Miller
and
S. P.
Walch
,
Int. J. Chem. Kinet.
29
,
253
(
1997
).
3.
M. R.
Berman
and
M. C.
Lin
,
J. Phys. Chem.
87
,
3933
(
1983
).
4.
L. J.
Medhurst
,
N. L.
Garland
, and
H. H.
Nelson
,
J. Phys. Chem.
97
,
12
275
(
1993
).
5.
A. J. Dean, R. K. Hanson, and C. T. Bowman, in Proceedings of the 23rd Symposium (International) on Combustion (The Combustion Institute, Pittsburgh, PA, 1990), p. 259.
6.
C. P. Fenimore, in Proceedings of the 13th Symposium (International) on Combustion (The Combustion Institute, Pittsburgh, PA, 1971), p. 373.
7.
J. A. Miller, M. C. Branch, W. J. McLean, D. W. Chandler, M. D. Smooke, and R. J. Kee, in Proceedings of the 20th Symposium (International) on Combustion (The Combustion Institute, Pittsburgh, PA, 1984), p. 373.
8.
D. Lindackers, M. Burmeister, and P. Roth, 23rd International Symposium on Combustion, 1990, Vol. 23, p. 251 (1990).
9.
M. R.
Manaa
and
D. R.
Yarkony
,
J. Chem. Phys.
95
,
1808
(
1991
).
10.
M. R.
Manaa
and
D. R.
Yarkony
,
Chem. Phys. Lett.
188
,
352
(
1992
).
11.
Q.
Cui
and
K.
Morokuma
,
Theor. Chem. Acc.
102
,
127
(
1999
).
12.
Q.
Cui
,
K.
Morokuma
,
J. M.
Bowman
, and
S.
Klippenstein
,
J. Chem. Phys.
110
,
9469
(
1999
).
13.
L. V. Moskaleva and M. C. Lin, “Colloquium on NOx,SOx and pollutant emission kinetics,” 2000.
14.
J. M. L.
Martin
and
P. R.
Taylor
,
Chem. Phys. Lett.
209
,
143
(
1993
).
15.
S. P.
Walch
,
Chem. Phys. Lett.
208
,
214
(
1993
).
16.
T.
Seideman
and
S. P.
Walch
,
J. Chem. Phys.
101
,
3656
(
1994
).
17.
S. P.
Walch
,
J. Chem. Phys.
103
,
4930
(
1995
).
18.
T.
Seideman
,
J. Chem. Phys.
101
,
3662
(
1994
).
19.
L. V.
Moskaleva
,
W. S.
Xia
, and
M. C.
Lin
,
Chem. Phys. Lett.
331
,
269
(
2000
).
20.
R. T.
Bise
,
H.
Choi
, and
D. M.
Neumark
,
J. Chem. Phys.
111
,
4923
(
1999
).
21.
R. T.
Bise
,
A. A.
Hoops
, and
D. M.
Neumark
,
J. Chem. Phys.
113
,
1
(
2000
).
22.
R. T. Bise, A. A. Hoops, H. Choi, and D. M. Neumark, in Imaging in Chemical Dynamics, edited by A. G. Suits and R. E. Continetti (American Chemical Society, Washington, DC, 2000), p. 296.
23.
E. P.
Clifford
,
P. G.
Wenthold
,
W. C.
Lineberger
,
G. A.
Petersson
, and
G. B.
Ellison
,
J. Phys. Chem. A
101
,
4338
(
1997
).
24.
G.
Herzberg
and
P. A.
Warsop
,
Can. J. Phys.
41
,
286
(
1963
).
25.
W.
Wu
,
G.
Hall
, and
T. J.
Sears
,
J. Chem. Soc., Faraday Trans.
89
,
615
(
1993
).
26.
G.
Herzberg
and
D. N.
Travis
,
Can. J. Phys.
42
,
1658
(
1964
).
27.
N.
Basco
and
K. K.
Yee
,
Chem. Commun. (Cambridge)
3
,
150
(
1968
).
28.
H. W.
Kroto
,
T. F.
Morgan
, and
H. H.
Sheena
,
Trans. Faraday Soc.
66
,
2237
(
1970
).
29.
C. W. Mathews, B. S. Pappas, and D. A. Ramsay, in NRC Spectroscopy Conference in Memory of Gerhard Herzberg, Ottawa, Canada, 1999.
30.
S.
Yamamoto
and
S.
Saito
,
J. Chem. Phys.
101
,
10
350
(
1994
).
31.
G.
Maier
,
J.
Eckwert
,
A.
Bothur
,
H. P.
Reisenauer
, and
C.
Schmidt
,
Liebigs Ann.
7
,
1041
(
1996
).
32.
Z. Liu, R. T. Bise, and D. M. Neumark (unpublished).
33.
F.-M.
Tao
,
W.
Klemperer
,
M. C.
McCarthy
,
C. A.
Gottlieb
, and
P.
Thaddeus
,
J. Chem. Phys.
100
,
3691
(
1994
).
34.
D. J.
Leahy
,
D. L.
Osborn
,
D. R.
Cyr
, and
D. M.
Neumark
,
J. Chem. Phys.
103
,
2495
(
1995
).
35.
R. E.
Continetti
,
D. R.
Cyr
,
R. B.
Metz
, and
D. M.
Neumark
,
Chem. Phys. Lett.
182
,
406
(
1991
).
36.
D. L.
Osborn
,
H.
Choi
,
D. H.
Mordaunt
,
R. T.
Bise
,
D. M.
Neumark
, and
C. M.
Rohlfing
,
J. Chem. Phys.
106
,
3049
(
1997
).
37.
D. L.
Osborn
,
D. J.
Leahy
,
D. R.
Cyr
, and
D. M.
Neumark
,
J. Chem. Phys.
104
,
5026
(
1996
).
38.
T. R.
Taylor
,
R. T.
Bise
,
K. R.
Asmis
, and
D. M.
Neumark
,
Chem. Phys. Lett.
301
,
413
(
1999
).
39.
J. M. B.
Bakker
,
J. Phys. E
6
,
785
(
1973
).
40.
J. M. B.
Bakker
,
J. Phys. E
7
,
364
(
1974
).
41.
D. P.
de Bruijn
and
J.
Los
,
Rev. Sci. Instrum.
53
,
1020
(
1982
).
42.
G. Herzberg, Molecular Spectra and Molecular Structure III. Electronic Spectra and Electronic Structure of Polyatomic Molecules (Van Nostrand Reinhold, New York, 1966).
43.
P. S. H.
Bolman
and
J. M.
Brown
,
Chem. Phys. Lett.
21
,
213
(
1973
).
44.
R. N.
Dixon
,
Can. J. Phys.
38
,
10
(
1960
).
45.
R. N.
Dixon
,
M. J.
Trenouth
, and
C. M.
Western
,
Mol. Phys.
60
,
779
(
1987
).
46.
S. A.
Wright
and
P. J.
Dagdigian
,
J. Chem. Phys.
104
,
8279
(
1996
).
47.
M. W.
Chase
, Jr.
,
J. Chem. Phys.
9
,
1
(
1998
).
48.
M.
Danielsson
,
P.
Erman
,
A.
Hishikawa
,
M.
Larsson
,
R.-K. E.
Sumame
, and
G.
Sundström
,
J. Chem. Phys.
98
,
9405
(
1993
).
49.
Y.
Huang
,
S. A.
Barts
, and
J. P.
Halpern
,
J. Phys. Chem.
96
,
425
(
1992
).
50.
E. P.
Clifford
,
P. G.
Wenthold
,
W. C.
Lineberger
,
G. A.
Petersson
,
K. M.
Broadus
,
S. R.
Kass
,
S.
Kato
,
C. H.
DePuy
,
V. M.
Bierbaum
, and
G. B.
Ellison
,
J. Phys. Chem. A
102
,
7100
(
1998
).
51.
A.
Hansel
,
C.
Scheiring
,
M.
Glantschniq
, and
W.
Lindinger
,
J. Chem. Phys.
109
,
1748
(
1998
).
52.
C. R.
Sherwood
,
M. C.
Garner
,
K. A.
Hanold
,
K. M.
Strong
, and
R. E.
Continetti
,
J. Chem. Phys.
102
,
6949
(
1995
).
53.
R. D. Levine, in Theory of Chemical Reaction Dynamics, edited by M. Baer (CRC, Boca Raton, FL, 1985), Vol. IV, p. 1.
54.
K. P. Huber and G. Herzberg, Constants of Diatomic Molecules (Van Nostrand Reinhold, New York, 1979).
55.
R. Schinke, Photodissociation Dynamics (Cambridge University Press, Cambridge, 1993).
56.
M.
Quack
and
J.
Troe
,
Ber. Bunsenges. Phys. Chem.
58
,
240
(
1974
).
57.
M.
Quack
and
J.
Troe
,
Ber. Bunsenges. Phys. Chem.
79
,
469
(
1975
).
58.
T. Baer and W. L. Hase, Unimolecular Reaction Dynamics (Oxford University Press, New York, 1996).
59.
G. E.
Busch
and
K. R.
Wilson
,
J. Chem. Phys.
56
,
3626
(
1972
).
60.
H. B.
Levene
and
J. J.
Valentini
,
J. Chem. Phys.
87
,
2594
(
1987
).
61.
A. F.
Tuck
,
J. Chem. Soc., Faraday Trans.
73
,
689
(
1977
).
62.
T. J.
Buttenhoff
,
K. L.
Carleton
, and
C. B.
Moore
,
J. Chem. Phys.
92
,
378
(
1990
).
63.
Q. Cui and K. Morokuma (private communication).
This content is only available via PDF.
You do not currently have access to this content.