We report an in situ Raman study of KClO4 irradiated with x-rays in a diamond anvil cell. Decomposition via KClO4 + hv → KCl + 2O2 was monitored via the O2 vibron at 2 GPa, 6 GPa, and 9 GPa. For all pressures, the vibron grew in intensity and then diminished after successive irradiation suggesting that O2 was diffusing away from the irradiated region. Surprisingly, the diffusion rate accelerated with pressure increase, indicating that the nonhydrostatic pressure gradient was likely driving molecular diffusion of oxygen. At 9 GPa, the vibron bifurcated suggesting that O2 exists as two forms: interstitial and bulk solid. This method can be employed to study molecular diffusion under extreme conditions.

1.
M.
Pravica
,
L.
Bai
,
C.
Park
,
Y.
Liu
,
M.
Galley
,
J.
Robinson
, and
N.
Bhattacharya
,
Rev. Sci. Instrum.
82
,
106102
(
2011
).
2.
M.
Pravica
,
L.
Bai
, and
N.
Bhattacharya
,
J. Appl. Crystallogr.
45
,
48
52
(
2012
).
3.
M.
Pravica
,
L.
Bai
,
C.
Park
,
Y.
Liu
,
M.
Galley
,
J.
Robinson
, and
D.
Hatchett
,
Rev. Sci. Instrum.
83
,
036102
(
2012
).
4.
M.
Pravica
,
L.
Bai
, and
Y.
Liu
,
Chem. Phys. Lett.
555
,
115
118
(
2013
).
5.
M.
Pravica
,
D.
Sneed
,
L.
Bai
, and
C.
Park
,
J. Phys. Chem.
117
,
2302
2306
(
2013
).
6.
M.
Pravica
,
B.
Hulsey
,
L.
Bai
,
D.
Sneed
,
Q.
Smith
, and
G.
Guardala
, “
Studies in useful hard x-ray induced chemistry: decomposition of poatassium haltes
,”
AIRAPT/APSSCCM Joint Conference Proceedings
(
2013
).
7.
Y.
Akahama
and
H.
Kawamura
,
Phys. Rev. B
54
(
22
),
R15602
R15605
(
1996
).
8.
H.
Giefers
and
M.
Pravica
,
J. Phys. Chem. A
112
(
15
),
3352
3359
(
2008
).
9.
N.
Toupry
,
H.
Poulet
,
M.
Le Postollec
,
R. M.
Pick
, and
M.
Yvinec
,
J. Raman Spectrosc.
14
(
3
),
166
177
(
1983
).
10.
L.
Liu
,
Y.
Bi
, and
J.
Xu
,
Chin. Phys. B
22
(
5
),
056201
(
2013
).
11.
M.
Pravica
,
D.
Sneed
,
L.
Bai
, and
Q.
Smith
, “
High pressure x-ray photochemical studies of carbon tetrachloride: Cl2 production and segregation
Chem. Phys. Lett.
(in press).
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