The reactions of N+(3P) ions with H2, HD, D2 are examined using guided ion beam tandem mass spectroscopy. Absolute reaction cross sections are measured from near thermal energies to 30 eV relative energy. The low energy cross section behavior is analyzed using empirical threshold models and phase space theory. The results are compared to other recent studies of the N++H2 system. The reaction endothermicity for N+(3P)+H2→NH++H, ΔH○0 =0.033±0.024 eV (0.76±0.55 kcal/mol), and the bond energy of NH+, D○0(N–H+) =3.51±0.03 eV (80.9±0.6 kcal/mol), are derived from the results.
REFERENCES
1.
E. A.
Gislason
, B. H.
Mahan
, C.‐W.
Tsao
, and A. S.
Werner
, J. Chem. Phys.
54
, 3897
(1971
).2.
3.
J. M.
Farrar
, S. G.
Hansen
, and B. H.
Mahan
, J. Chem. Phys.
65
, 2908
(1976
).4.
5.
S. G.
Hansen
, J. M.
Farrer
, and B. H.
Mahan
, J. Chem. Phys.
73
, 3750
(1980
).6.
G.
Eisele
, A.
Henglein
, P.
Botschwina
, and W.
Meyer
, Ber. Bungsenges. Phys. Chem.
78
, 1091
(1974
).7.
8.
S. Y.
Chu
, A. K. Q.
Siu
, and E. F.
Hayes
, J. Am. Chem. Soc.
94
, 2969
(1972
).9.
10.
M. A.
Gittins
and D. M.
Hirst
, Faraday Discuss. Chem. Soc.
62
, 67
(1977
).11.
12.
13.
C. F.
Bender
, J. H.
Meadows
, and H. F.
Schaefer
III, Faraday Discuss. Chem. Soc.
62
, 59
(1977
).14.
15.
N. G.
Adams
, D.
Smith
, and T. J.
Miller
, Mon. Not. R. Astron. Soc.
211
, 857
(1984
).16.
17.
J. B.
Marquette
, B. R.
Rowe
, G.
Duperyrat
, and E.
Roueff
, Astron. Astrophys.
147
, 115
(1985
).18.
19.
20.
21.
22.
Kent M. Ervin, Ph.D. thesis, University of California, Berkeley, 1986.
23.
S. G. Hansen, Ph.D. thesis, University of California, Berkeley, 1980.
24.
P. A. M.
Van Koppen
, P. R.
Kemper
, A. J.
Illies
, and M. T.
Bowers
, Int. J. Mass Spectrom. Ion Proc.
54
, 263
(1983
).25.
Quenching of the excited states produced by 50 eV electron impact requires less than 3 ms at pressures of 10 mTorr. [
W.
Frobin
, Ch.
Schlier
, K.
Strein
, and E.
Teloy
, J. Chem. Phys.
67
, 5505
(1977
).]26.
H. M.
Rosenstock
, K.
Draxl
, B. W.
Steiner
, and J. T.
Herron
, J. Phys. Chem. Ref. Data
6
, Suppl. 1
(1977
).27.
C. E. Moore, Atomic Energy Levels, Natl. Ref. Data Ser., Natl. Bur. Stand. No. 35 (U.S. GPO, Washington, D.C. 1935).
28.
I.
Wendel
, R. A.
Friedel
, and M.
Orchin
, J. Am. Chem. Soc.
71
, 1140
(1949
).29.
S. G.
Lias
, J. F.
Liebman
, and R. D.
Levin
, J. Phys. Chem. Ref. Data
13
, 695
(1984
).30.
S. T.
Gibson
, J. P.
Greene
, and J.
Berkowitz
, J. Chem. Phys.
83
, 4319
(1985
).31.
N. G.
Adams
, D.
Smith
, and J. F.
Paulson
, J. Chem. Phys.
72
, 288
(1980
).32.
Thepolarizability of hydrogen is [J. O. Hirshfelder, C. R. Curtiss, and R. B. Bird, Molecular Theory of Gases and Liquids (Wiley, New York, 1954), p. 947].
33.
M. E.
Weber
, J. L.
Elkind
, and P. B.
Armentrout
, J. Chem. Phys.
84
, 1521
(1986
).34.
Fits to the experimental cross sections use as the cross section for formation of the diatomic product ion, which is then multiplied by the dissociation probability given by the decay model (Ref. 33) and convoluted over the experimental energy distributions. Other model parameters are and or in the notation of Ref. 33.
35.
36.
A. Henglein, in Ion‐Molecule Reactions in the Gas Phase, edited by P. J. Ausloos (American Chemical Society, Washington, D.C. 1966), p. 63;
A.
Ding
, K.
Lacmann
, and A.
Henglein
, Ber. Bunsenges. Phys. Chem.
71
, 596
(1967
).37.
D. R.
Bates
, C. J.
Cook
, and F. J.
Smith
, Proc. Phys. Soc.
83
, 49
(1964
).38.
39.
40.
41.
C.
Lifshitz
, R. L. C.
Wu
, T. O.
Tiernan
, and D. T.
Terwilliger
, J. Chem. Phys.
68
, 247
(1978
).42.
J. D. Burley, K. M. Ervin, and P. B. Armentrout, J. Chem. Phys. (in press).
43.
P. B. Armentrout, in Structure, Reactivity, and Thermochemistry of Ions, NATO Adv. Study Institute Ser., edited by P. Ausloos, S. G. Lias, and D. Dixon (Reidel, Dordrecht, in press).
44.
45.
R. D. Levine and R. B. Bernstein, Molecular Reaction Dynamics (Oxford, New York, 1974), p. 46.
46.
47.
G. Herzberg, Molecular Spectra and Molecular Structure. I. Spectra of Diatomic Molecules (Van Nostrand Reinhold, Princeton, 1950).
48.
Rotational populations are calculated for the 305 K reactant gas temperature, taking into account nuclear spin statistics.
49.
The correction using the mean rotational energy is certainly valid in cases where the rotational energy is small relative to the translationl energy threshold, for example, (Ref. 21) and (Ref. 46).
50.
K.
Morokuma
, B. C.
Eu
, and M.
Karplus
, J. Chem. Phys.
51
, 5193
(1969
)., J. Chem. Phys.
51.
P.
Pechukas
, J. C.
Light
, and C.
Rankin
, J. Chem. Phys.
44
, 794
(1966
); , J. Chem. Phys.
J.
Lin
and J. C.
Light
, J. Chem. Phys.
45
, 2545
(1966
)., J. Chem. Phys.
52.
53.
54.
55.
56.
57.
In the notation of Refs. 55 and 56, the electronic degeneracy factors are for the reactant channel and for the product channel.
58.
59.
J. L. Elkind and P. B. Armentrout (unpublished).
60.
61.
Error limits are based on the 25% uncertainty cited for SIFDT experiments [
D.
Smith
, N. G.
Adams
, and E.
Alge
, Chem. Phys. Lett.
105
, 317
(1984
)].62.
D. Smith (private communication);
G. Dunn (private communication).
63.
Rates for 10 K are interpolated from the low temperature results for comparison with the PST rates.
64.
D. L.
Albritton
, I.
Dotan
, W.
Lindinger
, M.
McFarland
, J.
Tellinghuisen
, and F. C.
Fehsenfeld
, J. Chem. Phys.
66
, 410
(1977
);L. A.
Viehland
and E. A.
Mason
, J. Chem. Phys.
66
, 422
(1977
); , J. Chem. Phys.
S. L.
Lin
and J. N.
Bardsley
, J. Chem. Phys.
66
, 435
(1977
)., J. Chem. Phys.
65.
66.
K. P. Huber and G. Herzberg, Constants of Diatomic Molecules (Van Nostrand Reinhold, New York, 1979).
67.
68.
For a discussion of spin‐orbit effects on the reactivity of ion‐molecule reactions, see
K. M.
Ervin
and P. B.
Annentrout
, J. Chem. Phys.
85
, 6380
(1986
).69.
The analysis of the ion trap experiment (Ref. 18) relies on the LGS model as an estimate of the collision rate to derive the reaction rate from the measured reaction probability. Since the quadrupole term may change the overall collision rate, especially for low diatomic rotational states, this treatment could be inaccurate. Approximate collision models which include the quadrupole terms in the long‐range potential have been discussed [
T.
Su
and M. T.
Bowers
, Int. J. Mass Spectrom. Ion Phys.
17
, 309
, 424
(1976
);Ref. 20].
70.
In contrast to the present case, the reaction (Refs. 21 and 55) has a 0.4 eV translational energy threshold; at that energy the quadrupole interaction is probably not critically important.
71.
No further corrections are made for the spin‐orbit energy. Only ground state is present in the low‐temperature experiments (Refs. 17 and 18), but a thermal spin‐orbit state population is present in the SIFDT experiments. Correcting for spin‐orbit energy in the SIFDT value gives
72.
S. J.
Dunlavey
, J. M.
Dyke
, N.
Jonathan
, and A.
Morris
, Mol. Phys.
39
, 1121
(1980
).
This content is only available via PDF.
© 1987 American Institute of Physics.
1987
American Institute of Physics
You do not currently have access to this content.
