Chemistry Reference
In-Depth Information
Retardation mesh
MCP
I
90
I
990
M
+
Soft X-rays
II
0
M
+
Gas nozzle
Grounded
mesh
Retardation
mesh
Figure 1.
Schematic illustration of the experimental setup for ARPIS. Two identical ion detectors
are set at 0 and 90° with respect to the electric vector of the light.
1
u
or
dipole selection rule and the symmetry of the observed excited states is
1
u
. The minimal molecular orbital (MO) picture of N
2
is
(
X
1
g
)
(1
σ
g
)
2
(1
σ
u
)
2
(2
σ
g
)
2
(2
σ
u
)
2
(3
σ
g
)
2
(1
π
ux
)
2
(1
π
uy
)
2
(1
π
gx
)
0
(1
π
gy
)
0
(3
σ
u
)
0
The ionization threshold
E
th
of the N 1s electron is 409.9 eV, which is determined
by X-ray photoelectron spectroscopy [59]. The observed
gerade-ungerade
(g-u)
=
π
*
Rydberg
N
2
1.0
x10
N1s
-1
Double
excitation
σ
*
0.5
0.0
400
405
410
415
420
425
Photon Energy (eV)
Figure 2.
Soft X-ray absorption spectra of N
2
at the N 1s excitation and ionization region.
