Ⅲ-3
ChemistryⅢ -3. Chemistry

BL1U

Induced Chirality by Circularly Polarized UV Light for Photofunctional
Organic/Inorganic Hybrid Materials
1

T. Akitsu1, N. Sunaga1, N. Ishida1, M. Ito1, T. Konomi2 and M. Kato2

Department of Chemistry, Faculty of Science, Tokyo University of Science, Tokyo 162-8601, Japan
2
UVSOR Facility, Institute for Molecular Science, Okazaki 444-8585, Japan

Photofunctional organic/inorganic hybrid materials
containing chiral Schiff base Ni(II), Cu(II), and Zn(II)complexes involving azobenzene moiety have been
preparedandinvestigated(supra)molecularorientation induced by linearly polarized UV lightirradiation (optical dichroism, namely Weigert effect)with polarized electronic and IR spectroscopy or
induced by circularly polarized UV light irradiation(supramolecular chirality) with CD spectra [1-3].
However, in oriented samples, artifact CD peaks
prevents from obtaining proper data generally. So wehave employed wavelength selective UV light
generated by UVSOR BL-1U beamline. At the firstterm, circularly polarized UV light induced chiralsupramolecular orientation was observed withdifference CD spectra (before and after UV
irradiation), while at the second term, that linearlypolarized UV light induced changes resulted in littlechanges of CD spectra was confirmed as control
experiments.
New diastereomers of (achiral or chiral) Schiffbase Ni(II), Cu(II), and Zn(II) complexes with orwithout azobenzene moiety in ligands were prepared
as PMMA cast films (namely total 6 types oforganic/inorganic photofunctional hybrid materials).
These samples were irradiated linearly or circularly
polarized UV light at UVSOR BL-1U and compared
CD spectra before and after UV light irradiation toconfirm molecular orientation inside of the hybridmaterials.
Circularly polarized UV light at 260, 318, and 380
nm was irradiated for (0), 3, 5, and 8 min anddifferences of CD spectra (considered blank data toremove the effect artifact peaks) indicated increasing
CD peaks which suggested that chiral supramolecularorientation was induced. Light at 260 nm waseffective for inducing bands at about 300 nm for allcomplexes (in addition about 400 nm only for Zn(II)complex). Light at 318 and 380 nm was effective forinducing bands at about 300 and 500 nm for allcomplexes (in addition about 500 nm for Ni(II) andZn(II) complexes, and about 700 nm for Cu(II)complex).
On the other hand, similar discussion by difference
CD spectra before and after linearly polarized UVlight irradiation at selective wavelengths suggested
that no CD peaks could be observed atlong-wavelength region without noise peaks.
Generally in isotropic environment like solutions,
proper CD spectra can be obtained for chiral metal

complexes, which was ascribed to molecular chirality.
While no CD spectra could be observed for achiralmetal complexes. However, it was well known that inanisotropic environment like oriented samples (forexample, solid state or well-oriented films) not only
proper CD bands but also artifact CD bands could beobserved. In difference CD spectra, artifact peaks
were cancelled when changes about chirality did notoccurred even if there are molecular or
supramolecular chirality. In other words, althoughlinearly polarized UV light induced optical anisotropyof metal complexes in hybrid materials,
supramolecular chiral ordering was not influenced
even for chiral metal complexes.
In conclusion, emerging CD peaks in difference
CD spectra is attributed to supramolecular helicalorientation induced by circularly polarized UV lightirradiation for achiral as well as chiral metal
complexes. Additionally, UV light of certain
wavelengths can effectively induced molecularorientation.

Fig. 1. Chiral Schiff base metal complex without
azobenzene moiety [left] and its optimized structure[left].
[1] M. Ito and T. Akitsu, Contemporary Engineering
Sciences 7 (2014) 869.
[2] N. Hariu, M. Ito and T. Akitsu, Contemporary
Engineering Sciences 8 (2015) 57.
[3] N. Sunaga, S. Furuya, M. Ito, C. Kominato and T.
Akitsu, Computational Chemistry: Theories, Methods
and Applications (Nova Science Publishers, Inc., NY,
USA, 2014) 85.

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Ⅲ -3. Chemistry

BL1U

Photoionization Study of Helium Atoms Using Variable Polarization
Undulator
T. Kaneyasu1, Y. Hikosaka2, T. Konomi3, M. Katoh3, H. Iwayama3 and E. Shigemasa3
1

SAGA Light Source, Tosu 841-0005, Japan
Department of Environmental Science, Niigata University, Niigata 950-2181, Japan
3
UVSOR Facility, Institute for Molecular Science, Okazaki 444-8585, Japan2

Ⅲ-3

The nth harmonic radiation from a helical undulator
carries orbital angular momentum (OAM) of (n-1)ħ
per photon [1,2]. This accelerator-based method
efficiently generates the OAM photon beam in a wide
wavelength range. The APPLE-II undulator U1 in
UVSOR storage ring is suitable for generating the
OAM photon beam in the EUV region. We areplanning to investigate the interaction of the OAM
photon with gas-phase atoms in which violation of
the dipole selection rules is predicted [3].
For the feasibility study on performing thegas-phase experiment by using the undulator U1, weconstructed a test endstation equipped with thephotoelectron imaging spectrometer [4] as shown in
Fig.1. As a performance test of the experimental setup,
we measured the angular distributions of the He 1s
photoelectrons using the fundamental radiation withhorizontal linear and circular polarization. The peakenergy of the undulator radiation was roughly set to
30 eV. The experiments were performed during themachine study using the single-bunch mode. For
eliminating the background signals due to secondary
electrons emitted from the repeller plate of theimaging spectrometer, we applied the time gate signal
to the detector system.
Figure 2 shows the photoelectron images whichcorrespond to the projections of the three-dimensional
velocity distributions. The photon propagation
direction is along the Y-axis, while the electric vectorof the horizontally polarized radiation is parallel to
the X-axis. The images present broad structures
corresponding to the photoelectrons having 5 eV
kinetic energy. The broadness of the photoelectron
structures is mainly due to the bandwidth (~2 eVfwhm) of the undulator radiation.
Figure 3 shows the photoelectron angular
distributions converted from the images in Fig. 2.
using the peeling-analysis. The measured angular
distributions are in reasonable agreement with those
calculated for the dipole asymmetry parameter β=2.
This result confirms the usefulness of the present
method for measuring the photoelectron angular
distributions. We note that small deviations from the
β=2 patterns are probably due to image distortions
resulting from the stray magnetic field andimperfection in the background subtraction. For theexperiment on the OAM photoionization, we arepreparing a magnetic shield and a modified repeller
plate for the imaging spectrometer, both of which areessential for improving the image quality.

110

Fig. 1. Photo of the experimental setup constructed
at BL1U.

Fig. 2. He 1s photoelectron images measured for (a)horizontal linear and (b) circular polarization.

Fig. 3. He 1s photoelectron angular distributions
measured for (a) horizontal linear and (b) circularpolarization. Circles: experimental data, Solid curves:
calculation for β=2.
[1] S. Sasaki and I. McNulty, Phys. Rev. Lett. 100(2008) 124801.
[2] J. Bahrdt et al., Phys. Rev. Lett. 111 (2013)
034801.
[3] A. Picón et al., New J. Phys. 12 (2010) 083053.
[4] Y. Hikosaka and E. Shigemasa, J. Electron
Spectrosc. Relat. Phenom. 148 (2005) 5.

Ⅲ -3. Chemistry

BL3U

In Situ Soft X-Ray Absorption Spectroscopy Applied to Solid-Liquid
Heterogeneous Cyanopyrazine Hydration on Titanium Oxide Catalyst
H. Yuzawa, M. Nagasaka and N. Kosugi

Institute for Molecular Science, Okazaki 444-8585, Japan
We have compared this method with FT-IR
spectroscopy, which is typically used for the in situ
observation of catalytic reaction. FT-IR cannot detect
the characteristic peaks of PzCN (Fig. 2, purple line)in the PzCN solution used for the catalytic reaction(red line) because of the hindrance by the absorptionof H2O and EtOH. Therefore, in situ soft X-ray XAS
has a merit to detect minor liquid components in the
catalytic reaction.

In situ observation of liquid substrate conversion
process in solid-liquid heterogeneous catalytic
reaction is difficult because the bulk liquids (substrate
and/or solvent) hinder the objective spectral change[1]. This type of spectroscopy has been often carriedout by using ATR-IR and NMR, but these methods
still have some problems of the sensitivity and theoverlap of the target spectral signals.
We have developed a transmission-type in situ
liquid flow cell, which is able to optimize easily theliquid layer thickness for the soft X-ray XAS [2] anddemonstrated that this spectroscopic method iseffective to clarify the local structure of various liquid
solutions [3]. Thus, in the present study, we haveapplied this method to time and temperaturedependent in situ XAS measurements of solid-liquid
heterogeneous cyanopyrazine hydration to produce
pyrazinamide (PzCN + H2O → PzCONH2) on TiO2
catalyst [4].
The experiments were carried out in BL3U.
Suspension of catalyst was prepared by mixing of
PzCN (3 ml, 0.78 M), EtOH (5 ml), H2O (35 ml) andTiO2 (0.15 g). The suspension of thin layer (< 1 μm
thickness) was sandwiched between two 100
nm-thick Si3N4 membranes for C K-edge XAS (SiC
membranes for N K-edge XAS). Then, themeasurement was carried out under various reaction
temperatures from 323.2 to 344.5 K.
Figure 1a shows the C K-edge XAS spectra of
PzCN and PzCONH2 at 298K, and the hydration of
cyanopyrazine at 335 K. Three absorption peaks(285.4, 286.0 and 286.6 eV) are observed in PzCN
(red line) and one absorption peak (285.3 eV) in
PzCONH2 (blue line) are observed. All these peaks
are assigned to the C1s → π* excitation. In the
spectra of PzCN hydration (green lines), the intensity
ratio of the absorption peaks varies with the reaction
time, corresponding to the production of PzCONH2.
Figure 1b shows a logarithmic plot for the normalized
XAS intensity of PzCN, which is obtained from thefitting analysis of Fig. 1a (green lines) by using thestandard spectra of PzCN and PzCONH2. This plotshows linear relationship to the reaction time,
indicating that the observed catalytic reaction is thefirst-order reaction for the concentration of PzCN andthe slope of the line is a reaction rate constant. The
same results are obtained from C K-edge XAS atother temperatures and N K-edge XAS. Furthermore,
the obtained rate constants show linear relationship in
the Arrhenius plot (Ea = 80 kJ/mol). Thus, it isconfirmed that this analytical procedure is reasonable.

Ⅲ-3

Fig. 1. (a) C K-edge XAS spectra for the PzCN (0.78
M) (red line) and PzCONH2 (0.20 M) suspensions(blue line) at 298 K and catalytic hydration of PzCN
on TiO2 (green lines) at 335 K. (b) A logarithmic plotof the normalized XAS intensity of PzCN obtained
from the fitting analysis of green lines in (a).

Fig. 2. FT-IR spectra in transmission mode of pure
PzCN (purple line) and 0.78 M PzCN solution (redline) used in the catalytic hydration. They were
measured by using the same liquid cell as in the XAS.
[1] F. Zaera, Chem. Rev. 112 (2012) 2920.
[2] M. Nagasaka et al., J. Electron Spectrosc. Relat.
Phenom. 177 (2010) 130.
[3] M. Nagasaka et al., J. Phys. Chem. B 118 (2014)4388.
[4] H. Yuzawa et al., J. Phys. Chem. C, accepted.

111

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BL3U

Electronic Structure of Interfacial Water on Nanodiamonds in Colloidal
Dispersions
1

Ⅲ-3

T. Petit1, H. Yuzawa2, M. Nagasaka2, R. Yamanoi3, E. Osawa3, N. Kosugi2 and E. F. Aziz1,2,4

Institute of Methods for Materials Development, Helmholtz-Zentrum Berlin, Albert-Einstein-Str. 15, 12489 Berlin,
Germany2
Institute for Molecular Science, Myodaiji, Okazaki 444-8585, Japan
3
NanoCarbon Research Institute, AREC, Shinshu University, Ueda 386-8567, Japan
4
Freie Universität Berlin, FB Physik, Arnimallee 14, 14195 Berlin, Germany

The organization of water molecules close to solid
surfaces or around proteins differs significantly frompure water [1]. Reorganization of solvent molecules
is likely to occur around colloidal nanoparticles andits understanding is of outermost importance to better
estimate their reactivity and interaction withbiological moieties in aqueous environment.
Nevertheless, the structure of solvent moleculesaround nanomaterials in colloidal dispersion remains
largely unexplored. Nanodiamonds (NDs) are ofparticular interest for the investigation of interfacial
water since the existence of an ordered water shellranging from 2 to 4 water layers was recently
suggested.
The experiments were performed at BL3U in
UVSOR-III. Aqueous dispersions of NDs withdifferent sizes (ranging from 3 to 18 nm) and surface
chemistries were characterized by X-ray absorption
spectroscopy (XAS) in pure transmission using aflow cell described elsewhere [2]. By comparing these
XA spectra at oxygen K edge to pure water spectra,
the organization of water molecules in hydration
layers of NDs could be investigated.
Orientation of water molecules in the first solvation
shell is found to depend on the Zeta potential of NDs
as seen by changes in the pre-edge feature of O K
edge XA spectra. In particular, more hydrogen bonds
are broken at the surface of negatively-charged NDs
due to electrostatic interaction with carboxylategroups while water molecules donating two hydrogenbonds are dominant on positively-charged NDs.
Furthermore a long range order, having anelectronic signature close to high density amorphous
ice, was evidenced. As seen on Fig. 1, the X-ray
absorption increases dramatically at high NDs
concentration. This increase is significant comparedto aqueous ionic solution. The electronic structure ofwater is extremely different from bulk water due tothe strong contribution from interfacial water layers
around NDs. Unlike ions, NDs are too large to be
engulfed in a hydration cage which would break alimited amount of hydrogen bonds [3]. At the sametime, they are small enough to offer a large interface
and the surface polarization orients water moleculesaround them. It has to be noted that dispersions ofdetonation NDs at concentration around 8-10 wt%
forms highly viscous gel, which may be aconsequence of the long range ordering of watermolecules around NDs.
We could evidence that the electronic structure ofinterfacial water layers on NDs is very uncommon.
The long range ordering of water molecules on theirsurface may explain the high affinity of NDs forproteins adsorption or participate to their low toxicity.
These results have recently been submitted for
publication.

Fig. 1. (a) XAS of oxygen K-edge from water andaqueous dispersion of NDs at different concentrations
ranging from 1 to 8.6 wt%. (b) Pre/Main-edge ratios
for the different concentrations.
[1] J.-J. Velasco-Velez et al., Science 346 (2014) 831.
[2] M. Nagasaka et al., J. Phys. Chem. C 117 (2013)
16343.
[3] D. Chandler, Nature 437 (2005) 640.

112

Ⅲ -3. Chemistry

BL3U

Fluorination-Dependent Molecular Orbital Occupancy in Perfluorocarbons
1

T. Brandenburg1,2, T. Petit1, A. Neubauer1, K. Atak1,2, M. Nagasaka3, R. Golnak1,2,
N. Kosugi3 and E. F. Aziz1,2,3

Institute of Methods for Material Development, Helmholtz-Zentrum Berlin für Materialien und Energie,
Albert-Einstein-Straße 15, 12489 Berlin, Germany
2
Department of Physics, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany
3Institute for Molecular Science, Okazaki 444-8585, JapanThe family of perfluorocarbons has a wide range ofapplications in biomedicine and physical chemistry
due to their extraordinary properties. Many liquid
perfluorocarbons are known to show high density,
high viscosity as well as an especially high gas
solubility, and are often chemically and biologicalinert. Their ability to dissolve gases and their
biological inertness are exploited in the main
applications, such as tissue oxygenation or
post-operative treatment.
The
perfluoro
effect,inherenttoallperfluorocarbons, describes the energetic shifts of thespectral features upon complete fluorination ofhydrocarbons. This also led to a general rule for thedimensions of the energetic shifts depending on σ- or
π-character of the molecular orbitals (MO). Hence,
this effect can be used for experimental orbital
classification. In this context, a few experimental
studies have already been performed in the 1970s.
Many of them were based on photoelectron
spectroscopy. Since then, more complex theoreticalmodels and the introduction of new experimental
techniques give opportunities to investigate
perfluorocarbons.
Through the measurements performed at thebeamline BL3U in UVSOR-III we could obtain X-ray
absorption (XA) spectra of several perfluorocarbons
with sufficient signal intensity and without
experimental saturation effects. These spectra arecomplemented by resonant inelastic X-ray scattering(RIXS) spectra obtained at the LiXedrom endstationin BESSY II (Germany) [1, 2].
We could present fundamental insight into theenergetic shift induced by fluorination, the so-called
perfluoro effect, and a comprehensive picture of theelectronic structure of decalin as the parent
hydrocarbon molecule for perfluorodecalin based on
the XA, X-ray emission (XE) and RIXS
spectroscopic data [3]. In addition DFT calculations
for decalin, perfluorodecalin and stepwise fluorinateddecalin derivatives were performed. We observed achange in occupancy of MOs occurring for the
fluorinated hydrocarbons when reaching complete
fluorination in PFD.
This MO alteration may be one of the main reasonsfor the chemical and biological inertness of thering-shaped perfluorodecalin compared to decalin andthe corresponding partially fluorinated hydrocarbons.
Interestingly, the discovered orbital change in the XA

spectra could also be observed in the XE spectra in acomplementary way. To the best of our knowledge,
the observability of the perfluoro effect via XE
spectra was confirmed for the first time, and theorbital change originating from unoccupied decalin tooccupied PFD MOs was also discussed in relation to
the well-known high electronegativity of fluorine
atoms. Hence, the validity of this concept and its
extension to linear and also larger perfluoro systems
is of particular interest for a better understanding of
the special properties of perfluoro compounds andtheir application development.

Fig. 1. Sketch of the acquired data with an indicationof the discovered orbital alteration.
[1] K. M. Lange et al., Phys. Rev. B 85 (2012)
155104.
[2] C. Jung et al., Nucl. Instrum. Methods Phys. Res.
Sect. Accel. Spectrometers Detect. Assoc. Equip.
467-468 (2001) 485.
[3] T. Brandenburg et al., under review.

113

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Ⅲ -3. Chemistry

BL3U

Local Structures of Liquid Benzene Studied by Temperature-Dependent C
K-Edge Soft X-Ray Absorption Spectroscopy
M. Nagasaka1, H. Yuzawa1, K. Mochizuki1,2, E. Rühl3 and N. Kosugi1
1

Institute for Molecular Science, Myodaiji, Okazaki 444-8585, Japan
Department of Chemistry, Okayama University, Okayama 700-8530, Japan3
Physikalische Chemie, Freie Universität Berlin, Takustr. 3, D-14195 Berlin, Germany
2

Ⅲ-3

Benzene is liquid at room temperature. We reported
C K-edge X-ray absorption spectroscopy (XAS) of
benzene clusters formed by supersonic gas expansion
method, and investigated molecular interaction fromthe energy shift of C 1s → π* peak of benzene
clusters from benzene gas [1]. We also investigatedthe energy shift of C K-edge XAS of solid benzene,
which was grown in multilayers on Ru(0001) crystal
surface under vacuum condition revealing thegas-to-solid shift in the C 1s-regime [2]. However, themolecular interaction in liquid benzene has not yet
been investigated. In the present study, we havemeasured C K-edge XAS of liquid benzene atdifferent temperatures, and studied the temperatureeffect of the molecular interaction.
The experiments were performed at BL3U in
UVSOR-III. XAS spectra of liquid samples were
measured by a transmitted-type liquid flow cell [3].
The liquid layer was sandwiched between two 100
nm-thick Si3N4 membranes. The thickness of theliquid layer is controllable between 20 nm and 2000
nm by adjusting the He pressure.
Figure 1 shows C K-edge XAS of gaseous andliquid benzene at different temperatures. The C 1s →π* peak shows adiabatic (0, 0) transition andvibrational fine structures at higher photon energy.
Figure 2 shows the energy shifts of (0, 0) transition
peaks of liquid benzene from gaseous benzene as afunction of temperature. The π* peak shows a shift tolower photon energy by increasing the temperature of
the sample. The energy shift of liquid benzene
relative to the gas phase is 29.4 meV at 25.3 ºC. This
shift is smaller than in solid benzene and clusters,
which is 55 meV [2] and 70 meV [1], respectively.
The energy shift of the π* peak is caused by thebalance between the red-shift effect by induced
polarization with surrounding molecules and theblue-shift effect by exchange interaction between theunoccupied π* orbital with surrounding molecules [4].
Exchange interaction is effective in the short range,
so that the peak is shifted in condensed benzene tolower photon energy when the molecular distancebecomes longer. This is consistent with the fact thatbenzene molecules are increasingly separated fromeach other in the liquid as the temperature is raised.
Furthermore, the radial distribution function between
benzene molecules changes as a function oftemperature as evidenced by molecular dynamics
simulations. We have also investigated the114

interactions between benzene molecules by exciting
the C-H out-of-plane and C-H stretching vibration
mode by infrared spectroscopy. In the future, we will
discuss the molecular interaction in liquid benzene bycorrelating C K-edge XAS results with infrared
spectroscopy and molecular dynamics simulations.

Fig. 1. C K-edge XAS of gaseous and liquid benzene
at different temperatures. The inset shows the
maximum of the C 1s → π* transition in greater
detail.

Fig. 2. Energy shifts of C 1s → π* (0, 0) transition
peak of liquid benzene relative to gaseous benzene asa function of temperature.
[1] I. L. Bradeanu et al., Phys. Chem. Chem. Phys. 8(2006) 1906.
[2] R. Flesch et al., Phys. Chem. Chem. Phys. 14(2012) 9397.
[3] M. Nagasaka et al., J. Electron Spectrosc. Relat.
Phenom. 177 (2010) 130.
[4] M. Nagasaka et al., J. Electron Spectrosc. Relat.
Phenom. 183 (2011) 29.

Ⅲ -3. Chemistry

BL3U

Optimization of the Sample Position of the Liquid Thin Layer for SoftX-Ray Absorption Spectroscopy
M. Nagasaka, H. Yuzawa, T. Horigome and N. Kosugi
Institute for Molecular Science, Okazaki 444-8585, Japan

thickness of the liquid layers [2].
In summary, we have developed the XAS
measurement system that adjusts the liquid thickness
by controlling not only the helium pressure to
optimize the absorbance but also the sample position
to find a flat area of the sample thickness.

In order to measure X-ray absorption spectroscopy(XAS) of liquid samples in transmission mode, it isnecessary to control the liquid thickness. Recently, we
have developed a transmitted-type liquid flow cell tomeasure XAS of liquid samples [1]. The liquid layer
is sandwiched between two Si3N4 membranes, andthe thickness is controllable from 20 nm to 2000 nm
by adjusting helium pressures outside the membranes.
However, in this system, it is not able to control thesample position and it is difficult to confirm theflatness, or uniform thickness, of the thin liquid layer.
In the present study, we have developed an XAS
measurement system to sweep the position of theliquid layer, and have measured O K-edge XAS ofliquid water at different positions to find a flat area ofthe sample.
The experiments were performed at BL3U in
UVSOR-III. The system consists of ultrahigh vacuum
and atmospheric helium conditions, which areseparated by Si3N4 membranes (0.2 × 0.2 mm2). The
liquid cell that is sandwiched between two Si3N4
membranes (2 × 2 mm2) is in atmospheric condition,and is swept to different positions. XAS intransmission mode is measured by a photodiodedetector set behind the liquid cell. This system also
equips a silicon drift detector to measure XAS in
fluorescence mode.
Figure 1 shows O K-edge XAS of liquid water at
different sample positions. The inset of Fig. 2 shows
the images of X-ray transmission at 550 eV. O
K-edge XAS were measured by scanning the sample
positions shown in the arrow. O K-edge XAS shows
three features: The pre-edge at 535 eV, main-edge at
537 eV, and post-edge at 540 eV. The ratio of pre- andmain-edge is important to evaluate O K-edge XAS ofliquid water in transmission mode, and is proposed tobe 0.38 [2]. Figure 2 shows the ratio of pre- andmain-edge at different positions estimated by the O
K-edge XAS shown in Fig. 1. The liquid thickness at
different positions are also shown, which is estimatedfrom the edge-jump and the absorption coefficient ofliquid water. From 100 μm to 250 μm, the liquid
thickness is nearly constant. The ratio of pre- andmain-edge becomes 0.36-0.38 in this region. On theother hand, the liquid thickness is rapidly increased
above 300 μm. The ratio of pre- and main-edge isalso increased in this region. Because the beam sizeof soft X-rays is 200 × 200 μm2, XAS in this region
includes different thickness of liquid layers. The
previous study suggests that the ratio of pre- andmain-edge is increased at the mixtures of different

Ⅲ-3

Fig. 1. O K-edge XAS spectra of liquid water at
different sample positions (Y).

Fig. 2. Ratio of pre- and main-edge and the liquid
thickness at different sample positions (Y) estimatedfrom XAS shown in Fig. 1. The inset shows theimages of X-ray transmission at 550 eV. The arrow
indicates the sample position to measure XAS.
[1] M. Nagasaka et al., J. Electron Spectrosc. Relat.
Phenom. 177 (2010) 130.
[2] S. Schreck et al., Rev. Sci. Instrum. 82 (2011)
103101.

115

Ⅲ -3. Chemistry

BL3U

Detection of Intra- and Inter-Molecular Charge Transfer in Solution
by N K-Edge X-Ray Absorption Spectroscopy
1

Ⅲ-3

R. Golnak1,2, J. Xiao1, M. Tesch1, M. Yablonskikh1, M. Nagasaka3, T. Brandenburg1,4,
N. Kosugi3 and E. F. Aziz1,2,3

Institute of Methods for Material Development, Helmholtz-Zentrum Berlin für Materialien und Energie,
Albert-Einstein-Straße 15, 12489 Berlin, Germany
2
Department of Chemistry, Freie Universität Berlin, Takustraße 3, 14195 Berlin, Germany
3Institute for Molecular Science, Myodaiji, Okazaki 444-8585, Japan
4
Department of Physics, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany

Biological functions and chemical reactions mostly
happen in solution. To understand these processes it isof paramount interest to know the electronic structureof liquids and solutions. Core level spectroscopy
provides a probe to the electronic structure. In thiswork we investigated some derivatives of the Urea
molecule (Fig. 1(A)) in water and in dimethyl
sulfoxide (DMSO).
Through the measurements performed at thebeamline BL3U at UVSOR-III we could obtain X-ray
absorption (XA) spectra of the derivatives with
sufficient signal intensity and without experimental
saturation effects. These spectra are complemented byresonant inelastic X-ray scattering (RIXS) spectra
obtained at the LiXEdrom endstation at BESSY II(Germany) [1, 2]. Partial fluorescence yield (PFY)measurements were also done at BESSY II tocompare transmission mode absorption spectra
obtained at UVSOR-III.
What we observed is that the different
intra-molecular charge transfer, caused by different
molecular dipole moments in these three species,
leads to the energy shift of the N π* orbital below theionization potential (IP) (Fig. 1(A)), while thedifferent inter-molecular charge transfer, caused bydifferent surrounding solvent dipoles, results in anenergy shift of the N σ* orbital above the IP (Fig. 1(B)). Occupied states are normally more localized innature than the unoccupied states, and thus lessinfluenced by the charge transfer effect, as shown in
Fig. 2 that exhibits no energy shift between Urea andThiourea for the occupied states. N K-edge XAS is
sensitive to the molecular charge transfer, andtherefore can be used as a good indicator detecting
even minor changes of the chemical environment
around the specific site of interest.

Fig. 1. (A) N π* orbital below IP, indicated by theleft green line, has an energy shift, while N σ* above
the IP, marked by the right green line, share the sameenergy. (B) Different solvents do not shift the N π*
orbital, but the σ* instead, suggesting that the solvent
only affects the orbital above the IP.

Fig. 2. Occupied states of Urea and Thiourea inwater have almost identical energy positions, while
the unoccupied states have an energy shift, as alreadydiscussed in Fig. 1 (A), resulting in an local energy
gap opening for Urea, when compared with Thiourea.
[1] K. M. Lange et al., Phys. Rev. B 85 (2012)
155104.
[2] C. Jung et al., Nucl. Instrum. Methods Phys. Res.
Sect. Accel. Spectrometers Detect. Assoc. Equip.
467-468 (2001) 485.

116

Ⅲ -3. Chemistry

BL4U

Electrochemical Studies at BL4U STXM
1

S. M. Rosendahl1,2, A. P. Hitchcock1, M. Nagasaka3, Y. F. Wang3,
T. Horigome3, T. Ohigashi3 and N. Kosugi3

Chemistry & Chemical Biology, McMaster University, Hamilton, L8S4M1, Canada
2
Canadian Light Source, Saskatoon, SK S7N 5C9, Canada
3
Institute for Molecular Science, Okazaki 444-8585, JapanUVSOR BL4U STXM provides chemical imaging
with ~30 nm spatial resolution using 200-750 eV
X-rays. This project uses STXM to investigate
electrochemical systems, either prepared ex situ in
defined electrochemical states, or with in situ
modification of the electrochemical state of thesystem. Several generations of a device for in situ
flow electrochemistry have been developed at
UVSOR and in Canada. Here we report on progressin 2014, with data from two systems: (i) in situ
solution oxidation of FeSO4 (aq), and (ii) conversionof polyaniline (s) between emeraldine, the oxidized
quinoid form and leucoemeraldine, the reduced
aromatic form. Figure 1 is a photo of the latest
version of the in situ UVSOR flow cell. Reproduciblein situ flow in STXM has been achieved with thisdevice but, for various reasons, an in situ data set has
not yet been achieved.
In situ cyclic voltammetry and Fe 2p spectroscopy
of FeSO4 solutions have been carried out at BL3U
using an electrochemical cell [1,2]. We havedeveloped the Norcada/McMaster in situ cell from theconcept of this cell [3]. This system was examined by
STXM at the Fe 2p edge with in situ change of theelectrochemical state. Figure 2a presents Fe 2p3/2
spectra of the reduced and oxidized Fe ions extracted
from an image stack and set on an absolute intensity
scale (OD per nm). The Fe 2p3/2 stack was fit to these
spectra and a constant (water and Au electrodes),resulting in quantitative component maps which arepresented as a color coded composite in Fig.2b.
Surprisingly, the distribution of oxidation states was
opposite that expected since the WE was positive
relative to the CE when the stack was measured. It isalso surprising that the solution has a redox gradientacross it - one would expect diffusion to remove this.
This, and the lack of blue tinge in the inter-electroderegion, indicate there was very little water such thatthe solution phase is a gel.
Due to deterioration of the Au/Cr electrodes in
Fe(II) solutions, the system used to further develop
electrochemical STXM was changed to polyaniline(PANI), which has been studied with in situ STXM
earlier [4]. However the 1 M HCl used as electrolyte
damaged the stainless steel flow lines used in the
UVSOR in situ flow cell (Fig. 1). We were only able
to measure a dry sample, prepared ex situ at
McMaster on an early 2-electrode chip (‘PANI in a
drop’). PANI was electrodeposited on the left
electrode and left in the as-prepared oxidized state.
PANI electrodeposited on the right electrode waselectrochemically reduced after deposition. Figure 3apresents C 1s spectra of the oxidized and reduced
states extracted from selected regions of the dry, exsitu sample, nice examples of the C 1s performanceof the BL4U STXM. The spectra were used to fit C
1s stacks of the PANI deposits on each electrode;color coded composites are presented in Fig.3b &3b.
The left electrode has only oxidized PANI, while theright electrode has a combination of reduced andoxidized PANI. The oxidized PANI is probably fromPANI that was not electrically linked to the electrode.
Progress is steadily being made toward in situ flow
electrochemical STXM at BL4U

Ⅲ-3

Fig. 1. photograph of the UVSOR in situ flow cell.

Fig. 2. (a) Fe(II) andFe(III) spectra from stackof static cell with 0.1 M
FeSO4 (aq). (b) color
coded composite of mapsof Fe(II) (red), Fe(III)(green) and constant (blue)- electrodes.

Fig. 3. (a) C 1s spectra ofexsitu
depositedpolyaniline, in the reduced
and oxidized states. Color
coded composites of (b)left, and (c) right electrodes
which were converted
electro- chemically tooxidized and reduced states
in Canada.
[1] M. Nagasaka et al., J. Phys. Chem. C 117 (2013)
16343.
[2] M. Nagasaka, Rev. Sci. Instrum. 85 (2014)
104105.
[3] A. P. Hitchcock et al., J. Phys. Conf. Ser. (2015)
in press.
[4] D. Guay et al., Anal. Chem. 77 (2005) 3479.

117

Ⅲ -3. Chemistry

BL4B

Stability of Molecular Dications Studied by an Electron-Electron-Ion
Coincidence Method
K. Nakamura1, R. Mashiko1, K. Soejima1, E. Shigemasa2 and Y. Hikosaka1
1

Department of Environmental Science, Niigata University, Niigata 950-2181 Japan
2
UVSOR Facility, Institute for Molecular Science, Okazaki 444-8585 Japan

Fig. 1. Time-of-flight spectrum of electrons and ionsproduced from OCS at hν=318.6 eV.

Fig. 2. Correlation map for ion pairs detected incoincidence with C1s photoelectron from CH3OD.
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Ⅲ-3

Inner-shell ionization of a molecule and subsequentAuger decay usually produce the doubly-charged
molecular ion. The diaction is inherently unstableagainst the ion-pair dissociation, but it is known that,while the lifetime is of course state-dependent, some
low-lying dication states can be metastable in micro
second time scale or longer.
In this work, we have performed anelectron-electron-ion coincidence study of the OCS
diaction states. We have employed a magnetic-bottle
electron spectrometer adapted to ion detection. The
description is elsewhere [1]; here only brief accounts
are given. The spectrometer equipped with a strong
permanent magnet and a long solenoid coil, which
create an inhomogeneous magnetic field forming amagnetic mirror to collect the electrons from almost
the whole 4π solid angle. For coincidence detectionof the counterpart ions, a pulsed high voltage wasapplied to the ionization region, according to anelectron detection, and the formed ions wereintroduced into the same microchannel plate detector
for electron detection.
Figure 1 shows a time-of-flight spectrum ofelectrons and ions produced from OCS at hν=318.6
eV. While electron structures are exhibited blew 4000
ns, the peaks due to molecular ions are observed later
than 4000 ns. Figure 2 shows an energy correlation
map displaying the correlations between S2p
photoelectrons and Auger electrons. The horizontal
axis covers an electron energy range in which the S2p
photoelectrons appear, and the vertical axis does arange for the Auger electrons. At the photoelectronenergies for the formations of the spin-orbit
components of S2p-1, several structures associatedwith different OCS2+ states are observed. The verticalcuts at the photoelectron energies are plotted withblack and blue curves in Fig. 3, where two groups ofpeaks (0-4 eV and 4-10 eV) are observed. The red
and green curves are the coincidence Auger spectra
which are obtained by filtering with further
coincidence with OCS2+ ions. In the coincidence
spectra, the peaks in 4-10 eV are presented, but thepeaks below 4 eV disappear. This observation implies
that, while the states in the 4-10 eV range aremetastable, the states in the 0-4 eV range have much
shorter lifetimes.

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Fig. 3. Coincidence Auger spectra (black and blue)
and those with further coincidence with OCS2+ ions(red and green).
[1] A. Matsuda, M. Fushitani, C.-M. Tseng, Y.
Hikosaka, J. H. D. Eland and A. Hishikawa, Rev. Sci.
Instrum. 82 (2011) 103105.

118

Ⅲ -3. Chemistry

BL6U

Dissociation of CH3OH Dication Studied by an Electron-Ion Coincidence
MethodM. Higuchi1, T. Shirota2, K. Hoshina2, H. Iwayama3, E. Shigemasa3 and Y. Hikosaka1
1

Department of Environmental Science, Niigata University, Niigata 950-2181, Japan
Faculty of Pharmaceutical Sciences, Niigata University of Pharmacy and Applied Life Sciences, Niigata
956-8603, Japan
3
UVSOR Facility, Institute for Molecular Science, Okazaki 444-8585, Japan2

breaking.

Molecular absorption of a soft x-ray photon often
induces inner-shell photoionization, and the formed
core-hole usually relaxes via Auger decay. Because
two electrons are emitted through this sequential
process, the molecule with two positive charges is
produced. This dication is inherently instable due tothe Coulomb repulsion of the two positive charges,
and thus most of the dication states dissociate into ion
pairs. In this work, we have studied the ion-pairdissociation of the CH3OH dication states, by anelectron-ion coincidence method.
The experiment was performed at the undulator
beamline BL6U. We utilized an electron-ion
coincidence spectrometer [1,2] composed of a
toroidal electron analyzer and ion momentum
imaging analyzer. Figure 1 shows time-of-flight
spectra of ions produced after the C1s inner-shellionization of CH3OH and CH3OD, observed incoincidence with C1s photoelectrons emitted at hν=292.3 eV. While the structure around 2340 ns in the
CH3OH spectrum is allocated to the OH+ fragments,
the CH3OD spectrum also shows sizable intensity inthe same TOF range. In addition, the structure due tothe OD+ fragments can be observed around 2410 ns in
the CH3OD spectrum. These observations imply thatthe hydrogen atom in the OH+ fragment is not always
the one originally placed at the oxygen side in theneutral ground state of CH3OH, and thus suggests thatthe molecular structure can be largely deformed in the
dissociation pathway producing the OH+ fragment.
The correlation map in Fig. 2 presents ion pairs
detected in coincidence with C1s photoelectron from
CH3OD. One finds on the map structures
corresponding to the ion pairs of OD + + CH2+ and
OH+ + CDH+. While the former ion pair can beproduced by a simple CO bond breaking, theformation of latter needs a hydrogen exchange before
the bond breaking.
Figure 3 shows coincidence Auger spectra (red)which are filtered by detections with OD+ + CH2+ and
OH+ + CDH+, compared to the normal Auger
spectrum (black). The coincidence Auger spectrum
associated with OD+ + CH2+ (simple CO bondbreaking case) shows a peak at 41.3 eV. On the other
hand, the peak location is 39.3 eV in the coincidence
Auger spectrum associated with OH+ + CDH+
(hydrogen exchange case). This observation implies
that fairly-stable dication state(s) lies around 39.3 eV,
where hydrogen exchange precedes the bondFig. 1. Time-of-flight spectra of ions produced after
the C1s inner-shell ionizations of CH3OH (black) andCH3OD (red), observed in coincidence with C1s
photoelectrons emitted at hν=292.3 eV.

Fig. 2. Correlation map for ion pairs detected incoincidence with C1s photoelectron from CH3OD.

Fig. 3. Coincidence Auger spectra (red) which arefiltered by detections with OD+ + CH2+ and OH+ +CDH+, compared to the normal Auger spectrum(black).
[1] T. Kaneyasu, Y. Hikosaka and E. Shigemasa, J.
Electron Spectrosc. Rel. Phenom. 156-158 (2007)
279.
[2] Y. Hikosaka, Y. Shibata, K. Soejima, H. Iwayama
and E. Shigemasa, Chem. Phys. Lett. 603 (2014) 46.

119

Ⅲ-3

Ⅲ -3. Chemistry

BL6U

Spectator Auger Decays of 1,1,1-Trifluoroethane across the F K Threshold
1

T. Kaneda1, K. Okada1, H. Iwayama2,3 and E. Shigemasa2,3Department of Chemistry, Hiroshima University, Higashi-Hiroshima 739-8526, Japan
2
UVSOR Facility, Institute for Molecular Science, Okazaki 444-8585, Japan3
School of Physical Sciences, The Graduate University for Advanced Studies (SOKENDAI), Okazaki 444-8585,
Japan

Ⅲ-3

Inner-shell excitation of gaseous molecules results
in a specific dissociation through Auger processes.
Recently, we found in the F KVV Auger spectra of
cis-hexafluorocyclobutane (cis-c-C4H2F6, HFCB) thatspectator decay predominates and that the peaks
change almost linearly with photon energy [1]. These
shifts are known as “spectator shifts” arising from thecore-hole screening of a spectator electron for an
outgoing electron. In addition to the spectator shifts, afluorine atomic Auger peak was observed. This peak
implies the presence of ultrafast dissociation (UFD).
It takes place during the lifetime of the core-hole state
before Auger electron emission. It is rare that the
UFD can be observed clearly in relatively large
molecules.
In this study, to investigate spectator shifts
quantitatively, we measured resonant/normal Auger
spectra of 1,1,1-trifluoroethane (CH3CF3) across the F
K threshold as a function of photon energy with asmall energy step and a higher electron energy
resolution. Because the CH3CF3 molecule has ahigher symmetry than that of HFCB, we expect a
simple spectrum, making spectator shifts clearer.
The experiments were performed on the soft X-ray
beamline BL6U. A main chamber was equipped witha high-resolution hemispherical electron analyzer(MBS-A1). The monochromatized radiation was
focused onto a center of a gas cell containing thesample gas and the pressure of the main chamber was
kept at 1.0 × 10-3 Pa during the measurements.
Electron spectra were recorded in the F 1s region (hν= 682.0–702.0 eV) with a photon energy step of 0.5
eV.
Figure 1 shows some of the resonant/normal Auger
spectra plotted on the electron kinetic energy scale.
The spectra have been obtained by subtracting thecontribution from the photoelectron acquired at hν =683.0 eV. The spectator shifts can be evaluated using
the F 1s ionization threshold of CH 3CF3: 694.1 eV [2].
One can see that the electronic relaxation processes
are dominated by spectator Auger decay, in contrast
with low probability of participator Auger decay. Thisis the same trend as in the case of HFCB [1]. On theanalogy of HF [3], we assign the intense bands around
650, 625 and 605 eV to the transitions to the final
state of vo-1vo-1, vo-1vi-1 and vi-1vi-1, respectively. The
notation vo represents an outervalence orbital such as
F 2p, and vi is an innervalence. The positions ofspectator Auger bands (S1–S3) shift with the photon
energy leading to the normal Auger bands (N1–N3).

120

This is similar to the results of HFCB, but thepositions seem to vary in a non-linear manner
because each of these spectator peaks is composed ofseveral components. In addition, the shapes of these
spectra change dramatically with the excitationenergy. We need to find the correct components toevaluate the spectator shifts. The analysis is inprogress now.

Fig. 1. Resonant and normal Auger spectra of
CH3CF3 acquired at some photon energies across theF K threshold.
[1] T. Kaneda, S. Ishikawa, K. Okada, H. Iwayama, L.
Ishikawa and E. Shigemasa, UVSOR Activity Report2013 41 (2014) 119.
[2] W. L. Jolly, K. D. Bomben and C. J. Eyermann, At.
Data Nucl. Data Tables 31 (1984) 433.
[3] R. W. Shaw, Jr. and T. D. Thomas, Phys. Rev. A.
11 (1975) 1491.

Ⅲ -3. Chemistry

BL6U

Specific Auger Decay and Photofragmentation of cis-Hexafluorocyclobutane
1

S. Ishikawa1, K. Okada1, H. Iwayama2,3 and E. Shigemasa2,3Department of Chemistry, Hiroshima University, Higashi-Hiroshima 739-8526, Japan
2
UVSOR Facility, Institute for Molecular Science, Okazaki 444-8585, Japan3
School of Physical Sciences, Graduate University for Advanced Studies (SOKENDAI), Okazaki 444-8585,
Japan
Inner-shell excited states of molecules relax into
various molecular cationic states through Auger
decays. The resultant cations are in general unstableand dissociate into fragment ions. In our previous
study we observed site-specific fragmentation of theinner-shell excited cis-hexafluorocyclobutane (HFCB,
cis-c-C4H2F6) molecule. The yield spectra of thefragment ions with C–F bond(s) have a peak at theσCC* resonance, while those of the ions without C–F
bonds do not. This infers that the resonant state
decays to particular Auger-final states, connecting to
specific fragmentation channels. The purpose of thisstudy is to illuminate such Auger processes with themeasurements of Auger-electron–photoion coincidence (AEPICO) spectra.
The experiments have been performed on the soft
X-ray beamline BL6U. The experimental setup has
been described in a previous report [1]. Synchrotron
radiation was irradiated at right angles to the effusive
beam of the gaseous HFCB sample. The electrons
traveling through a double toroidal analyzer tube
were detected with a position sensitive detector(RoentDek, DLD40). The pass energy was set to 400
eV in this study. Photofragment ions were extracted
toward the time-of-flight spectrometer by a pulsed
electric field applied just after the Auger electron
detection. The light intensity was monitored
downstream on the beamline during the measurements. The coincidence data were acquired at thephoton energies of 707.5, 695.0, 688.5, 310.0, 297.0
and 292.8 eV.
The branching fraction of the Auger processes isfound to depend on the resonant states. Figure 1ashows some typical resonant Auger spectra plotted on
the final-state energy scale. The normal Auger
spectrum measured under the same experimental
conditions is also given at the top on the double
ionization energy scale. Two peaks are found in thisenergy range. They are assigned to spectator Auger
decays [2]. The intensity ratio of the two peaks varies
with the photon energy: 0.36 at 707.5 eV, 0.33 at
695.0 eV and 0.41 at 688.5 eV. This indicates that thepresence of a spectator electron clearly affects theAuger decays.
A noticeable feature can be seen in the coincidence
spectra. Panel b shows the Auger electron yield
curves coincident with the C2H0,1F+ and C2H0-2+ ions,which have been obtained by editing the AEPICO
data acquired at 695.0 eV. Auger electrons forming
the S2 peak are almost exclusively coincident with121

the ions without C–F bonds, except for CH0,1F+ (notshown in Fig. 1). This fact represents that the
suppression of the S2 peak is responsible for thesite-specific fragmentation at the F K-edge: smaller
branching fraction to form the S2 peak makes theyield of the ions without C–F bonds lower.
The resonant Auger spectra at the C K-edge are inclear contrast to those at the F edge. The spectrum forthe σCC* resonance at 297.0 eV has a strong, broad
peak at around the final-state energy of 40 eV.
Abundant photofragments in coincidence with thecorresponding Auger electrons are the ions with C–Fbond(s). The processes to show the site specificity are
different between at the F edge and at the C edge.

Fig. 1. Resonant and normal Auger spectra of HFCB
measured at three excitation energies (a) and thecomponents coincident with C2H0,1F+ and C2H0-2+ at
the photon energy of 695.0eV (b).
[1] S. Ishikawa, K. Okada, H. Iwayama, L. Ishikawa
and E. Shigemasa, UVSOR Activity Report 2012 40(2013) 58.
[2] T. Kaneda, S. Ishikawa, K. Okada, H. Iwayama
and E. Shigemasa, UVSOR Activity Report 2013 41(2014) 119.

Ⅲ-3

Ⅲ -3. Chemistry

BL6U

Ultrafast Dissociation of Core Excited CF4 Molecules Studied by an
Auger-Electron–Ion Coincidence Method
1

2

Ⅲ-3

H. Iwayama1,2 and E. Shigemasa1,2

UVSOR Facility, Institute for Molecular Science, Okazaki 444-8585, Japan
School of Physical Sciences, The Graduate University for Advanced Studies (SOKENDAI), Okazaki 444-8585,
Japan
Figures 2(a) and 2(b) show ion images of CF3+ ion
fragments, which were taken in coincident withelectrons at the peaks A and B, respectively. The
angular distribution of CF3+ ions is considerably
anisotropic in Fig. 2(a), while almost isotropic
angular distributions are seen in Fig. 2(b). Twoisland-like structures along the polarization vector are
clearly observed in Fig. 2(a). This means that thecore-excited CF4 molecules lead to immediate CF
bond breaking, which is the direct evidence of theultrafast dissociation for the peak A. The detailed data
analyses are now in progress.

Molecular inner-shell excitation into ananti-bonding orbital causes a nuclear motion. In somecases, the nuclear dynamics is so fast that dissociation
takes place before Auger electron emission. This
process is referred to as ultrafast dissociation andobserved in hydrogen halide molecules such as HBr[1] and HCl [2].
Recently, we found a signature of ultrafast
dissociation following C 1s→σ*(t2) core excitation in
CF4 by using two dimensional electron spectroscopy[3]. We observed Auger electrons from both CF3*
fragment and CF4* parent molecule. This means that
the Auger decay and dissociation processes take placeon the same time scale and significantly compete witheach other.
In the present work, we have investigatedanisotropic angular distributions of ejected CF3+ ionsby using an Auger-electron–ion coincidence method.
Since the CF bond involved in the C 1s→σ*(t2) core
excitation is immediately broken due to the ultrafast
dissociation, anisotropic angular distributions ofejected the CF3+ ions are expected.
The Auger-electron–ion coincidence measurements
were carried out on the undulator beamline BL6U at
UVSOR. The radiation from an undulator was
monochromatized by a variable included angle variedline-spacing plane grating monochromator. The
electrons ejected at 54.7° with respect to the electric
vector of the incident radiation were analyzed inenergy by a double toroidal analyzer (DTA), whileions were extracted from the interaction region into a
momentum spectrometer by a pulsed electric fieldaccording to the electron detection. Arrival positionon the detector and time-of-flights of ions wererecorded for every event. The pass energy of the DTA
was set to 200 eV for observing the Auger electrons.
The energy resolution was about 1.9 eV. All signals
from the detectors were recorded with an 8ch TDC
board. We used the photon energy of 298.5 eV, whichcorresponds to the C 1s → σ*(t2) resonance.
Figure 1 shows total and coincidence Auger spectrawith CF3+ ions. It is seen that the CF3+ ions arecoincident with electrons at the binding energy of
15~25 eV, where two peaks A and B are detected. For
higher binding energies, we observed smaller
fragment ions such as CF2+, CF+ and C+ (not shownhere). From the previous work [3], the peaks A and B
are attributable to the Auger electrons from the CF3*
fragment and CF4* parent molecules, respectively.

Fig. 1. Total and coincident Auger electron spectrumwith CF3+ ions.

Fig. 2. Ion images of CF3+ ions coincident with
Auger electrons at (a) peak A and (b) peak B.
[1] M. Morin and I. Nenner Phys. Rev. Leet. 56(1986) 1913.
[2] H. Aksela et al., Phys. Rev. A 41 (1990) 600.
[3] M. N. Piancastelli, R. Guillemin, M. Simon, H.
Iwayama and E. Shigemasa, J. Chem. Phys. 138(2013) 23430.

122