Specific examples are given of artifacts in photoionization‐efficiency curves that result from the use of a discrete‐line light source. A comparative technique is used to distinguish this false structure from genuine structure marking energy levels above the ionization potential (I.P.). More accurate I.P.'s than previously available are given for HCl, CH3Cl, CH3NO2, CH3CN, C2H4, C3H6, C2H2 and new values for CH4, CD4, C2H6, C3H8.

1.
A. J. C.
Nicholson
,
J. Chem. Phys.
39
,
954
(
1963
).
2.
Table I, Ref. k.
3.
Table I, Ref. p.
4.
Table I, Ref. o.
5.
W. C. Price (personal communication).
6.
J. E.
Collin
,
Bull. Soc. Roy. Sci. Liege
32
,
133
(
1963
), quotes five values ranging from 11.1–11.7 eV.
7.
R. J.
Kandel
,
J. Chem. Phys.
23
,
84
(
1955
).
8.
Rather than postulate an unusual rearrangement, it seems simpler to attribute this small CH3NO+ current near 11.2 eV to CH3NO produced by pyrolysis on the mass‐spectrometer filament. If this were true there would be no CH3NO+ ions contributing to the P.E. curve.
9.
Table I, Ref. r.
10.
This sentence is quoted [
C. J.
Danby
,
Ann. Rept. Progr. Chem. Soc. London
60
,
152
(
1963
)] without the saving clause beginning “with a sensitivity.” This omission, in my opinion, gives the quotation a meaning that was not intended by its originators.
11.
These values agree exactly with photoionization I.P. of 12.71 and 12.87 eV determined by
V. H.
Dibeler
,
M.
Krauss
,
R. M.
Reese
, and
F. N.
Harlee
,
J. Chem. Phys.
42
,
3791
(
1965
). I am indebted to Dibeler for letting me see a preprint of this paper.
12.
Table I, Ref. s.
13.
A.
Terenin
and
F.
Vilessov
,
Advanc. Photochem.
2
,
392
(
1964
).
14.
M. F. A.
El‐Sayed
,
M.
Kasha
, and
Y.
Tanaka
,
J. Chem. Phys.
34
,
334
(
1961
).
15.
J. D. Morrison (personal communication).
16.
F.
Norling
,
Z. Physik
104
,
638
(
1937
).
17.
J.
Momigy
,
Nature
199
,
1179
(
1963
).
18.
P. G.
Wilkinson
,
Astrophys. J.
138
,
778
(
1963
).
19.
S.
Geltman
,
Phys. Rev.
102
,
171
(
1956
).
20.
J. D.
Morrison
,
J. Appl. Phys.
28
,
1409
(
1957
).
21.
J. D.
Morrison
,
J. Chem. Phys.
40
,
2488
(
1964
).
22.
J. W.
McGowan
,
E. M.
Clarke
,
H. P.
Hanson
, and
R. F.
Stebbings
,
Phys. Rev. Letters
13
,
620
(
1964
).
23.
D. C.
Frost
and
C. A.
McDowell
,
Proc. Roy. Soc. (London)
A124
,
194
(
1957
).
24.
S.
Tsuda
,
C. E.
Melton
, and
W. H.
Hamill
,
J. Chem. Phys.
41
,
689
(
1964
).
This content is only available via PDF.
You do not currently have access to this content.