The transient absorption spectra of a number of compounds in solution at room temperature have been measured with picosecond‐scale time resolution and unprecedented accuracy and reliability. It is found that the spectra of benzophenone, xanthone, 9‐fluorenone, p‐benzoquinone, acridine, quinoxaline, t‐stilbene all show significant evolution following excitation with the 353 nm third harmonic of a mode‐locked Nd:glass laser. These spectral changes provide evidence for previously unrecognized photophysical behavior in the systems studied, including vibrationally nonthermalized triplet states in benzophenone which persist for tens of picoseconds, and formerly unobserved singlet absorptions in acridine, quinoxaline, fluorenone, and benzoquinone. The inadequacy of single wavelength probing techniques in deducing the dynamics of complex molecular systems such as these is demonstrated by the large extent to which spectra of different states overlap. In many cases a reinterpretation of previous single wavelength results is required because of the presence of vibrationally and electronically unrelaxed species. The apparatus used here to obtain the high quality visible transient spectra is described and its performance characterized.

1.
A.
Laubereau
and
W.
Kaiser
,
Rev. Mod. Phys.
50
,
607
(
1978
).
2.
R. M. Hoehstrasser and P. Prasad, in Excited States, Vol. 1, edited by E. C. Lim (Academic, New York, 1974).
3.
T. J.
Aartsma
and
D. A.
Wiersma
,
Chem. Phys. Lett.
54
,
415
(
1978
).
4.
K. B. Eisenthal, in Topics in Applied Physics, Vol. 18, edited by S. L. Shapiro (Springer‐Verlag, Berlin, 1977).
5.
B. L. Greene, R. M. Hoehstrasser, and R. B. Weisman, in Springer Series in Chemical Physics, Vol. 4, Picosecond Phenomena, edited by C. V. Shank, E. P. Ippen, and S. L. Shapiro (Springer‐Verlag, Berlin, 1978); p. 12.
6.
R. R.
Alfano
and
S. L.
Shapiro
,
Phys. Rev. Lett.
24
,
584
(
1970
).
7.
R. R.
Alfano
and
S. L.
Shapiro
,
Chem. Phys. Lett.
8
,
631
(
1971
).
8.
G. E.
Busch
,
R. P.
Jones
, and
P. M.
Rentzepis
,
Chem. Phys. Lett.
18
,
178
(
1973
).
9.
D.
Magde
and
M. W.
Windsor
,
Chem. Phys. Lett.
27
,
31
(
1974
).
10.
D.
Magde
,
M. W.
Windsor
,
D.
Holton
, and
M.
Gouterman
,
Chem. Phys. Lett.
29
,
183
(
1974
).
11.
R. M. Hoehstrasser and A. C. Nelson, in Lasers in Physical Chemistry and Biophysics, edited by J. Joussot‐Dubien (Elsevier, Amsterdam, 1975); p. 305.
12.
R. W.
Anderson
and
R. M.
Hoehstrasser
,
J. Phys. Chem.
80
,
2155
(
1976
).
13.
R. W.
Anderson
,
R. M.
Hoehstrasser
, and
H. J.
Pownall
,
Chem. Phys. Lett.
43
,
224
(
1976
).
14.
A. J. Campillo and S. L. Shapiro, in Topics in Applied Physics, Vol. 18, edited by S. L. Shapiro (Springer‐Verlag, Berlin, 1977).
15.
A.
Penzkofer
,
A.
Seilmeier
, and
W.
Kaiser
,
Opt. Commun.
14
,
363
(
1975
).
16.
W.
Lee Smith
,
P.
Liu
, and
N.
Bloembergen
,
Phys. Rev. A
15
,
2396
(
1977
).
17.
R. M.
Hoehstrasser
,
H.
Lutz
, and
G. W.
Scott
,
Chem. Phys. Lett.
24
,
162
(
1974
).
18.
S.
Voelker
,
R. M.
Macfarlane
, and
J. H.
van der Waals
,
Chem. Phys. Lett.
53
,
8
(
1978
).
19.
R. M. Hoehstrasser and C. Nyi, J. Chem. Phys. (to be published).
20.
G. R.
Fleming
,
O. L. J.
Guzeman
, and
S. H.
Lin
,
J. Chem. Soc. Faraday Trans. II
70
,
1074
(
1974
).
21.
A.
Nitzan
and
J.
Jortner
,
Chem. Phys. Lett.
15
,
350
(
1972
).
22.
R. B.
Weisman
and
S. A.
Rice
,
Spectrosc. Lett.
8
,
329
(
1975
).
23.
A.
Savitzky
and
M. J. E.
Golay
,
Anal. Chem.
36
,
1627
(
1964
).
24.
O.
Teschke
,
E. P.
Ippen
, and
G. R.
Holtom
,
Chem. Phys. Lett.
52
,
233
(
1977
).
25.
P. M.
Rentzepis
,
Science
169
,
239
(
1969
).
26.
R. W.
Anderson
,
R. M.
Hoehstrasser
,
H.
Lutz
, and
G. W.
Scott
,
Chem. Phys. Lett.
32
,
204
(
1975
).
27.
D. S.
McClure
and
P. L.
Hanst
,
J. Chem. Phys.
23
,
1772
(
1955
).
28.
S.
Dym
and
R. M.
Hoehstrasser
,
J. Chem. Phys.
51
,
2458
(
1969
).
29.
R. M.
Hoehstrasser
and
J. E.
Wessel
,
Chem. Phys. Lett.
19
,
156
(
1973
).
30.
A.
Chakrabarti
and
N.
Hürota
,
J. Phys. Chem.
80
,
2966
(
1976
).
31.
R. A.
Caldwell
,
Tetrahedron Lett.
2121
(
1969
).
32.
T.
Kobayashi
and
S.
Nagakura
,
Chem. Phys. Lett.
43
,
429
(
1976
).
33.
L. Hallidy, H.‐B. Lin, and M. R. Topp, in Springer Series in Chemical Physics, Vol. 4, Picosecond Phenomena, edited by C. V. Shank, E. P. Ippen, and S. L. Shapiro (Springer‐Verlag, Berlin, 1978); p. 314.
34.
D. R.
Kemp
and
G.
Porter
,
Proc. R. Soc. London Ser. A
326
,
117
(
1971
).
35.
E. C. Lim, in Excited States, Vol. 3, edited by E. C. Lim (Academic, New York, 1977) and references therein.
36.
Y.
Hirata
and
L.
Tanaka
,
Chem. Phys. Lett.
41
,
336
(
1976
).
37.
V.
Sundstrom
,
P. M.
Rentzepis
, and
E. C.
Lim
,
J. Chem. Phys.
66
,
4287
(
1977
).
38.
L. J.
Noe
,
E. O.
Degenkolb
, and
P. M.
Rentzepis
,
J. Chem. Phys.
68
,
4435
(
1978
).
39.
J. B. Birks, Photophysics of Aromatic Molecules (Wiley, New York, 1970).
40.
Cited in Ref. 11; unpublished results from this laboratory.
41.
G. W. Scott, L. D. Talley, and R. W. Anderson, in Springer Series in Chemical Physics, Vol. 4, Picosecond Phenomena, edited by C. V. Shank, E. P. Ippen, and S. L. Shapiro (Springer‐Verlag, Berlin, 1978) in press.
42.
J. Saltiel, in Organic Photochemistry, Vol. 3, edited by O. L. Chapman (Marcel Dekker, New York, 1973).
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