The CF+ and CF3+ fragment ion yield curves from C2F4 have been remeasured by photoionization mass spectrometry. Fits with appropriate model curves yield the appearance potentials AP0(CF3+C2F4)=13.721±0.005 eV and AP0(CF+/C2F4)=13.777±0.005 eV and an accurate difference in ionization potentials, IP(CF)−IP(CF3)=0.055±0.003 eV. With the existing photoelectron value IP(CF)=9.11±0.01 eV, this produces IP(CF3)=9.055±0.011 eV. The CF3+ fragments from CF3Cl, CF3Br, and CF3I have also been remeasured, and their ion yield curves fitted with model functions. The experimentally derived AP0(CF3+/CF3Cl)<12.867±0.008 eV has been found to be only an upper limit. The Analogous CF3+CF3+ fragment yield curves from CF3Br and CF3I produce AP0(CF3+/CF3Br)=12.095±0.005 eV and AP0(CF3+/CF3I)=11.384±0.005 eV, leading to D0(CF3−Br)=70.1±0.3 kcal/mol (70.8±0.3 kcal/mol at 298 K) and D0(CF3−I)=53.7±0.3 kcal/mol (54.3±0.3 kcal/mol at 298 K). Based on tabulated values for ΔHf(CF3Br) and ΔHf(CF3I), which appear to be inconsistent by ∼1 kcal/mol, a compromise value of ΔH298 f∘(CF3)=−111.4±0.9 kcal/mol (−110.7±0.9 kcal/mol at 0 K) is selected, resulting in ΔH298f∘(CF3+)=97.4±0.9 kcal/mol (98.1±0.9 kcal/mol at 0 K). Additionally, IP(CF4)≡AP0(CF3+/CF4)=14.67±0.04 eV can be inferred. From data on C2F4, ΔH298f∘(CF)=62.5±1.1 kcal/mol (61.7±1.1 kcal/mol at 0 K) can be deduced. Many earlier literature values for appearance potentials of CF3+ from CF3X, leading to very low ΔHf(CF3+) and/or IP(CF3) values, are demonstrated to be in error.

1.
Scientific Assessment of Stratospheric Ozone, World Meteorological Organization Global Ozone Research and Monitoring Project, Report No. 20 (UN Environment Program, WMO, Geneva, 1990).
2.
Scientific Assessment of Ozone Depletion, World Meteorological Organization Global Ozone Research and Monitoring Project, Report No. 25 (UN Environment Program, WMO, Geneva, 1991).
3.
See, for example,
T. J.
Wallington
,
W. F.
Schneider
,
D. R.
Worsnop
,
O. J.
Nielsen
,
J.
Sehested
,
W. J.
Debruyn
, and
J. A.
Shorter
,
Environ. Sci. Technol.
28
,
320
A
(
1994
), and references therein.
4.
See, for example,
A. R.
Ravishankara
,
A. A.
Turnipseed
,
N. R.
Jensen
,
S. B.
Barone
,
M.
Mills
,
C. J.
Howard
, and
S.
Salomon
,
Science
263
,
71
(
1994
), and references therein.
5.
See, for example,
M. K. W.
Ko
,
N.-D.
Sze
,
J. M.
Rodríguez
,
D. K.
Weistenstein
,
C. W.
Heisey
,
R. P.
Wayne
,
P.
Biggs
,
C. E.
Canosa-Mas
,
H. W.
Sidebottom
, and
J.
Treacy
,
Geophys. Res. Lett.
21
,
101
(
1994
), and references therein.
6.
M. W.
Chase
,
C. A.
Davies
,
J. R.
Downey
, Jr.
,
D. J.
Frurip
,
R. A.
Mc-Donald
, and
A. N.
Syverud
, JANAF Thermochemical Tables, 3rd ed.,
J. Phys. Chem. Ref. Data
14
, Suppl.
1
(
1985
).
7.
A. N. Syverud, Quarterly Tech. Report T-0009–2Q-69 (Dow Chemical, Midland, 1969).
8.
L. V. Gurvich, I. V. Veyts, and C. B. Alcock, Thermodynamic Properties of Individual Substances, 4th ed. (Hemisphere, New York, 1991), Vol. 2.
9.
D. F.
McMillen
and
D. M.
Golden
,
Annu. Rev. Phys. Chem.
33
,
493
(
1982
).
10.
S. G.
Lias
,
J. E.
Bartmess
,
J. F.
Liebman
,
J. L.
Holmes
,
R. D.
Levin
, and
W. G.
Mallard
,
J. Phys. Chem. Ref. Data
17
, Suppl.
1
(
1988
).
11.
W.
Tsang
,
J. Phys. Chem.
90
,
414
(
1986
).
12.
J. A. Kerr and S. J. Moss, CRC Handbook of Bimolecular and Thermomolecular Gas Reactions (CRC, Boca Raton, FL, 1981), Vol. 1.
13.
J. A. Kerr and M. J. Parsonage, Evaluated Kinetic Data on Gas Phase Addition Reactions: Reactions of Atoms and Radicals with Alkenes, Alkynes and Aromatic Compounds (Butterworths, London, 1982).
14.
S. S.
Kumaran
,
M.-C.
Su
,
K. P.
Lim
, and
J. V.
Michael
,
Chem. Phys. Lett.
243
,
59
(
1995
).
15.
S. S.
Kumaran
,
M.-C.
Su
,
K. P.
Lim
,
J. V.
Michael
,
A. F.
Wagner
,
L. B.
Harding
, and
D. A.
Dixon
,
J. Phys. Chem.
100
,
7541
(
1996
).
16.
J. H.
Kiefer
,
R.
Sathyanarayana
,
K. P.
Lim
, and
J. V.
Michael
,
J. Phys. Chem.
98
,
12
278
(
1994
).
17.
C.
Lifshitz
and
W. A.
Chupka
,
J. Chem. Phys.
47
,
3439
(
1967
).
18.
T. A.
Walter
,
C.
Lifshitz
,
W. A.
Chupka
, and
J.
Berkowitz
,
J. Chem. Phys.
51
,
3531
(
1969
).
19.
Walter et al. (Ref. 18) refer to this data as “T. A. Walter, W. A. Chupka, and J. Berkowitz, to be published;” the paper, for some reason, never appeared in print.
20.
Y.
Loguinov
,
V. V.
Takhistov
, and
L. P.
Vatlina
,
Org. Mass Spec.
16
,
239
(
1981
).
21.
M.
Horn
,
M.
Oswald
,
R.
Oswald
, and
P.
Botschwina
,
Ber. Bunsen Ges. Phys. Chem.
99
,
323
(
1995
).
22.
J. M.
Dyke
,
A. E.
Lewis
, and
A.
Morris
,
J. Chem. Phys.
80
,
1382
(
1984
).
23.
H. M.
Rosenstock
,
K.
Draxl
,
B. W.
Steiner
, and
J. T.
Herron
, Energetics of Gaseous Ions,
J. Chem. Phys. Ref. Data
6
, Suppl.
1
(
1977
).
24.
C. J.
Noutary
,
J. Res. Natl. Bur. Stand.
72A
,
479
(
1968
).
25.
I. G.
Simm
,
C. J.
Danby
,
J. H. D.
Eland
, and
P. I.
Mansell
,
J. Chem. Soc. Faraday Trans. II
72
,
426
(
1976
).
26.
J. M.
García de la Vega
and
E.
San Fabián
,
Chem. Phys.
151
,
335
(
1991
).
27.
J. M.
García de la Vega
,
E.
Mena
,
B.
Miguel
, and
E.
San Fabián
,
J. Phys. Chem.
99
,
12
135
(
1995
).
28.
G.
Hagenow
,
W.
Denzer
,
B.
Brutschy
, and
H.
Baumgärtel
,
J. Phys. Chem.
92
,
6487
(
1988
).
29.
I.
Powis
,
Mol. Phys.
39
,
311
(
1980
).
30.
J. C.
Creasey
,
H. M.
Jones
,
D. M.
Smith
,
R. P.
Tuckett
,
P. A.
Hatherly
,
K.
Codling
, and
I.
Powis
,
Chem. Phys.
174
,
441
(
1993
), and references therein.
31.
D. M.
Smith
,
R. P.
Tuckett
,
K. R.
Yoxall
,
K.
Codling
,
P. A.
Hatherly
,
J. F. M.
Aarts
,
M.
Stankiewicz
,
J. Chem. Phys.
101
,
10559
(
1994
), and references therein.
32.
M.
Tichy
,
G.
Javahery
,
N. D.
Twiddy
, and
E. E.
Ferguson
,
Int. J. Mass Spectrom.
79
,
231
(
1987
).
33.
E. R.
Fisher
and
P. B.
Armentrout
,
Int. J. Mass Spectrom.
101
,
R1
(
1990
), and references therein.
34.
J. M.
Ajello
,
W. T.
Huntress
, Jr.
and
P.
Rayermann
,
J. Chem. Phys.
64
,
4746
(
1976
).
35.
H. W.
Jochims
,
W.
Lohr
, and
H.
Baumgärtel
,
Ber. Bunsen Ges. Phys. Chem.
80
,
130
(
1976
);
see also
H.
Schenk
,
H.
Ortel
, and
H.
Baumgärtel
,
Ber. Bunsen Ges. Phys. Chem.
83
,
683
(
1979
).
36.
J. C.
Creasey
,
D. M.
Smith
,
R. P.
Tuckett
,
K. R.
Yoxall
,
K.
Codling
, and
P. A.
Hatherly
,
J. Phys. Chem.
100
,
4350
(
1996
).
37.
J. T.
Clay
,
E. A.
Walters
,
J. R.
Grover
, and
M. V.
Willcox
,
J. Chem. Phys.
101
,
2069
(
1994
).
38.
D. W.
Berman
and
J. L.
Beauchamp
,
Int. J. Mass Spectrom.
39
,
47
(
1981
).
39.
R.
Bombach
,
J.
Dannacher
,
J.-P.
Stadelmann
,
J.
Vogt
,
L. R.
Thorne
, and
J. L.
Beauchamp
,
Chem. Phys.
66
,
403
(
1982
).
40.
A. A. Radzig and B. M. Smirnov, Reference Data on Atoms, Molecules and Ions (Springer, Berlin, 1985);
see also: C. E. Moore, Atomic Energy Levels, Vols. 1–3 (National Bureau of Standards, Washington, DC, 1958).
41.
R. A.
Morris
,
A. A.
Viggiano
,
J. M.
Van Doren
, and
J. F.
Paulson
,
J. Phys. Chem.
96
,
3051
(
1992
).
42.
See, for example,
P.
Guyon
and
J.
Berkowitz
,
J. Chem. Phys.
54
,
1814
(
1971
).
43.
(a)
B.
Ruscic
, and
J.
Berkowitz
,
J. Phys. Chem.
97
,
11451
(
1993
);
B.
Ruscic
, and
J.
Berkowitz
, (b)
J. Chem. Phys.
100
,
4498
(
1994
);
B.
Ruscic
, and
J.
Berkowitz
, (c)
101
,
7795
(
1994
); ,
J. Phys. Chem.
B.
Ruscic
, and
J.
Berkowitz
, (d)
101
,
7975
(
1994
); ,
J. Phys. Chem.
(e)
101
,
10936
(
1994
); ,
J. Phys. Chem.
(e)
R. L.
Asher
,
E. H.
Appleman
, and
B.
Ruscic
,
J. Chem. Phys.
105
,
9781
(
1996
).,
J. Phys. Chem.
44.
R. L.
Kelly
, Atomic and Ionic Spectrum Lines Below 2000 Å: Hydrogen Through Krypton,
J. Phys. Chem. Ref. Data
16
, Suppl.
1
(
1987
).
45.
J.-Y. Roncin and F. Launay, Atlas of the Vacuum Ultraviolet Emission Spectrum of Molecular Hydrogen, J. Phys. Chem. Ref. Data, Monograph 4 (1994).
46.
P. C.
Haarhoff
,
Mol. Phys.
7
,
101
(
1963
).
47.
See, for example, G. N. Lewis and M. Randall. Thermodynamics, 2nd ed. (McGraw Hill, New York, 1961).
48.
W.
Zhang
,
G.
Cooper
,
T.
Ibuki
, and
C. E.
Brion
,
Chem. Phys.
151
,
343
(
1991
).
49.
(a)
T.
Cvitas
,
H.
Güsten
, and
L.
Klasinc
,
J. Chem. Phys.
67
,
2687
(
1977
);
(b)
T.
Cvitas
,
H.
Güsten
,
L.
Klasinc
,
I.
Novak
, and
H.
Vancik
,
Z. Naturforsch.
33a
,
1528
(
1978
);
(c) See also,
T.
Cvitas
,
I.
Novak
, and
L.
Klasinc
,
Int. J. Quantum Chem.: Quantum Chem. Symp.
21
,
737
(
1987
).
50.
From JANAF (Ref. 6), which is almost identical to Gurvich et al. (Ref. 8): ΔHf 298(CF4) = −223.0±0.3 kcal/mol (−221.6±0.3 kcal/mol at 0 K), ΔHf 298(CF3Cl) = −169.2±0.8 kcal/mol (−168.0±0.8 kcal/mol at 0 K), ΔHf 298(CF3Br) = −155.1±0.7 kcal/mol (−152.2±0.7 kcal/mol at 0 K), ΔHf 298(CF3I) = −140.8±0.8 kcal/mol (−139.4±0.8 kcal/mol at 0 K), and ΔHf 298(F) = 18.97±0.07 kcal/mol (−18.47±0.07 kcal/mol at 0 K), ΔHf 298(Cl) = 28.992±0.002 kcal/mol (28.590±0.002 kcal/mol at 0 K), ΔHf 298(Br) = 26.74±0.01 kcal/mol (28.18±0.01 kcal/mol at 0 K), ΔHf 298(I) = 25.52±0.01 kcal/mol (25.61±0.01 kcal/mol at 0 K).
This content is only available via PDF.
You do not currently have access to this content.