Studies of the near ultraviolet absorption spectra of α‐, β‐, and γ‐picoline vapor have been made in low and medium dispersion. Conclusive evidence is found for two electronic transitions in the vicinities of 35500 and 38500 cm−1. The former transition is interpreted as an allowed A1B2 transition resulting from the excitation of an sp2 nonbonding electron of the nitrogen atom into the first unfilled π‐orbital of the ring. The latter transition is considered an allowed A1B1 transition resulting from the excitation of a π ring electron. The A1B2 system exhibits narrow headless bands similar to the first absorption bands in pyridine. It is of weak intensity comparable to that of the forbidden A1gB2u transition in benzene. The A1B1 system, which is much stronger, consists of broad diffuse bands. There is evidence that this system may be overlapped by another transition in β‐picoline.

1.
V.
Henri
and
P.
Angenot
,
Compt. Rend.
200
,
1032
(
1935
);
V.
Henri
and
P.
Angenot
,
Compt. Rend.
201
,
895
(
1935
);
V.
Henri
and
P.
Angenot
,
J. Chim. Phys.
33
,
641
(
1936
).
2.
H.
Sponer
,
Revs. Modern Phys.
16
,
224
(
1944
).
3.
H.
Sponer
and
H.
Stücklen
,
J. Chem. Phys.
14
,
101
(
1946
).
4.
F.
Baker
and
E. C. C.
Baly
,
J. Chem. Soc.
91
,
1122
(
1907
);
J. E.
Purvis
,
J. Chem. Soc.
95
,
294
(
1909
);
J. E.
Purvis
,
97
,
692
(
1910
); ,
J. Chem. Soc.
E.
Herrmann
,
Z. Wiss. Phot.
18
,
253
(
1919
).
5.
We are indebted to Drs. J. Duchesne and L. d’Or for such data for α‐picoline, from the Ph.D. dissertation of P. Angenot at Liège in 1936.
6.
H.
Sponer
and
J. H.
Rush
,
J. Chem. Phys.
17
,
587
(
1949
).
7.
Betty Jane Fax, Ph.D. thesis, M.I.T. (1950).
8.
E. F. G.
Herington
,
Disc. Faraday Soc.
9
,
26
(
1950
).
9.
Harold P.
Stephenson
,
Phys. Rev.
76
,
199A
(
1949
);
Harold P.
Stephenson
,
83
,
246A
(
1951
).,
Phys. Rev.
10.
Am. Petroleum Institute Research Project 44 at the National Bureau of Standards. Catalog of Ultraviolet Spectrograms, Serial No. 213, 2‐methyl‐pyridine, contributed by Mellon Institute.
11.
S. K. K.
Jatkar
,
Indian J. Phys.
10
,
23
(
1936
).
12.
R.
Manzoni‐Ansidei
,
Boll. Sci. Facolta Chim. Ind. Bologna
1
,
137
,
184
(
1940
).
13.
Herz
,
Kahovec
, and
Kohlrausch
,
Z. Physik. Chem.
B53
,
124
(
1943
).
14.
J.
Lecomte
,
Compt. Rend.
207
,
395
(
1938
);
J.
Lecomte
,
J. Phys. Radium
9
,
512
(
1938
).
15.
Barnes, Gore, Liddell and Williams, Infrared Spectroscopy (Reinhold Publishing Corporation, New York, 1944), p. 96.
16.
F. T.
Riley
and
K. C.
Bailey
,
Proc. Roy. Irish Acad.
38B
,
450
(
1929
).
17.
H. C.
Brown
and
G. K.
Barbaras
,
J. Am. Chem. Soc.
69
,
1137
(
1947
).
18.
P. A.
van der Meulen
and
R. F.
Mann
,
J. Am. Chem. Soc.
53
,
451
(
1931
).
19.
E. R.
Hopke
and
G. W.
Sears
,
J. Chem. Phys.
19
,
1345
(
1951
).
20.
H. P. Stephenson, Ph.D. thesis (Duke University, 1952).
21.
M.
Kasha
,
Disc. Far. Soc.
9
,
14
(
1950
).
22.
Gertrud P.
Nordheim
and
H.
Sponer
,
J. Chem. Phys.
20
,
285
(
1952
).
23.
Sponer
,
Nordheim
,
Sklar
, and
Teller
,
J. Chem. Phys.
7
,
207
(
1939
).
24.
A.
Turkevich
and
M.
Fred
,
Revs. Modern Phys.
14
,
246
(
1942
).
25.
Ginsburg
,
Robertson
, and
Matsen
,
J. Chem. Phys.
14
,
511
(
1946
).
26.
C. D.
Cooper
and
M. L. N.
Sastri
,
J. Chem. Phys.
20
,
607
(
1952
).
27.
K. S.
Pitzer
and
D. W.
Scott
,
J. Am. Chem. Soc.
65
,
803
(
1943
).
28.
K. W. F.
Kohlrausch
and associates,
Monatsh. Chem.
72
,
268
(
1939
);
K. W. F.
Kohlrausch
and associates,
74
,
175
(
1942
); ,
Monatsch. Chem.
K. W. F.
Kohlrausch
and associates,
76
,
200
(
1947
).,
Monatsch. Chem.
29.
G.
Herzberg
and
Teller
,
Z. Physik Chem.
B21
,
410
(
1933
);
H.
Sponer
and
E.
Teller
,
Revs. Modern Phys.
13
,
75
(
1941
).
30.
F.
Halverson
and
R. C.
Hirt
,
J. Chem. Phys.
19
,
711
(
1951
).
31.
C.
Reid
,
J. Chem. Phys.
18
,
1673
(
1950
).
This content is only available via PDF.
You do not currently have access to this content.