<s>
In	O
physics	O
and	O
chemistry	O
,	O
photoemission	B-Algorithm
orbital	I-Algorithm
tomography	I-Algorithm
(	O
POT	O
;	O
sometimes	O
called	O
photoemission	B-Algorithm
tomography	I-Algorithm
)	O
is	O
a	O
combined	O
experimental	O
/	O
theoretical	O
approach	O
which	O
reveals	O
information	O
about	O
the	O
spatial	O
distribution	O
of	O
individual	O
molecular	O
orbitals	O
.	O
</s>
<s>
Experimentally	O
,	O
it	O
uses	O
angle-resolved	O
photoemission	O
spectroscopy	O
(	O
ARPES	O
)	O
to	O
obtain	O
constant	O
binding	O
energy	O
photoemission	O
angular	O
distribution	O
maps	O
,	O
so-called	O
tomograms	B-Algorithm
(	O
also	O
known	O
as	O
momentum	O
maps	O
or	O
-maps	O
)	O
,	O
to	O
reveal	O
information	O
about	O
the	O
electron	O
probability	O
distribution	O
in	O
molecular	O
orbitals	O
.	O
</s>
<s>
Theoretically	O
,	O
one	O
rationalizes	O
these	O
tomograms	B-Algorithm
as	O
hemispherical	O
cuts	O
through	O
the	O
molecular	O
orbital	O
in	O
momentum	O
space	O
.	O
</s>
<s>
Then	O
,	O
the	O
photocurrent	O
arising	O
from	O
one	O
particular	O
initial	O
state	O
is	O
proportional	O
to	O
the	O
Fourier	B-Algorithm
transform	I-Algorithm
of	O
the	O
initial	O
state	O
wave	O
function	O
modulated	O
by	O
the	O
weakly	O
angle-dependent	O
polarization	O
factor	O
:	O
</s>
<s>
Moreover	O
,	O
a	O
reconstruction	O
of	O
molecular	O
orbital	O
densities	O
in	O
real	O
space	O
via	O
an	O
inverse	O
Fourier	B-Algorithm
transform	I-Algorithm
and	O
applying	O
an	O
iterative	O
phase	O
retrieval	O
algorithm	O
has	O
also	O
been	O
demonstrated	O
.	O
</s>
<s>
The	O
present	O
understanding	O
is	O
that	O
the	O
information	O
retrieved	O
from	O
photoemission	B-Algorithm
orbital	I-Algorithm
tomography	I-Algorithm
should	O
be	O
interpreted	O
as	O
Dyson	O
orbitals	O
.	O
</s>
