Ⅲ-3
Chemistry
ChemistryⅢ -3. Chemistry
BL1U
BL1U

Molecular Orientation Induced by Irradiation Polarized or Optical Vortex
Wavelength Selective UV Light to Azo-metal Complexes in Polymer Films
T. Akitsu1, S. Yagi1, S. Yamazaki1, M. Yoshida1, T. Haraguchi1,
M. Fujiki2, M. Fujimoto3 and M. Katoh3

Faculty of Sciences, Tokyo University of Science, Tokyo 162-8601, Japan
2
Graduate School of Materials Sciences, NAIST, Nara 630-0192, Japan
3
UVSOR Synchrotron Facility, Institute for Molecular Science, Okazaki 444-8585, Japan1

In recent years, studies on photochemical materials
using optical vortex UV light have attracted attention.
In contrast to circularly polarized light, a light vortex
having a spiral wave front and carrying an orbital
angular momentum gives a torque when irradiated on
photofunctional materials. In this context, we haveattempted molecular orientation control by irradiating
linearly and/or circularly polarized (and opticalvortex) UV light to polymer films containing (chiral or
achiral) dinuclear Schiff base metal complexes [1, 2]
with/without
azo-dyes
exhibiting
cis-trans
photoisomerization and Weigert effect. Herein, we
employed azo-containing mononuclear Schiff basemetal complexes (Fig. 1) in PMMA films formolecular orientation phenomenon induced by several
types of UV light irradiation.
We prepared them in the common procedures andmeasured their UV-vis spectra or other data. Amongthese four complexes, we selected a complex with
M=Zn(II) and R=H (PazZn) appearing intense peak at
380 nm for the following photo-irradiation experiments.
We have also checked cis-trans photisomerization of
azo-moiety of ligand by wavelength selective UV lightirradiation and Weigert effect, which is linearlypolarized light induced anisotropic molecularorientation, and supramolecular chiral arrangement
induced by circularly polarized light irradiation.
Based on these experiments using a conventional
laboratory light source, the irradiation wavelength ofthe optical vortex was set to 317 nm, Δλ = about 30
nm. Photo-illumination with linearly polarized light(LPL), circularly polarized light (CPL), OV and
optical vortex (OV) of UV light was carried out using
UVSOR beam line BL1U as listed in Table 1. For
example, Fig. 2. depicts typical results of CD spectra.

Table 1. Experimental conditions.
Sample Light Time/min
1
PazZn
CPL
1
2
PazZn
CPL
10, 103
PazZn
CPL
10, 65
4
PazZn
LPL
30
5
PazZn
CPL
60
6
PazZn
CPL
60
7
PazZn
CPL
60
8
PazZn
LPL
180
9
PMMA
CPL
60
10
PazZn
OV
218
11
PazZn
OV
201, 205
12
PazZn
OV
267, 195
13
PazZn
CPL
30, 30Condensing

V
V
V

Ⅲ-3
V

Fig. 2. CD spectra of PazZn under the condition 11
after 0 (above) and 205 (below) min.

Fig. 1. Molecular structures of metal complexes.

[1] H. Nakatori, T. Haraguchi and T. Akitsu, Symmetry
10 (2018) 147.
[2] M. Takase, S. Yagi, T. Haraguchi, S. Noor and T.
Akitsu, Symmetry 10 (2018) 760.

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Ⅲ03- 1 -Ⅲ -3. Chemistry
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BL1U

Absolute Asymmetric Synthesis with Circularly Polarized LightJ. Yao and C. Yang

Key Laboratory of Green Chemistry & Technology of Ministry of Education, State Key Laboratory of Biotherapy,
Sichuan University, Chengdu 610065, China
Circularly polarized light (CPL) is without doubt
truly chiral electromagnetic radiation in the sense
described above and therefore CPL should in theory beable to induce absolute asymmetric synthesis.[1] We
have studied the chiral induction effects of circularly
polarized light (CPL) for photo-responsive compounds(Fig. 1). The racemic compounds will be exposure in the
CPL and to produce the excess enantiomer by thedifferential absorption and the process can be detectedby CD spectra. We have irradiated 8 samples on thesedays and the presentationis as follows (Table 1).

Samples
2 (YJB-4-42)

3 (YJB-4-39D)
4 (HTT-5B)

Ⅲ-3

5 (HTT-7B)
6 (ap-BBET)

L-CPL 1.8 mW
280 nm 5 min +L-CPL 0.58 mW
510 nm 7+16
min
R-CPL 280 nm
5 min

Fig. 1. Photo-Responsive Compounds.
Table 1. The Results of CPL Experiments.
Samples
1 (YJB-4-41)

Irradiations
R-CPL 1.6 mW
309 nm 5 min
R-CPL 1.6 mW
309 nm 35 min

R-CPL 3.6 mW
359 nm 30 min
L-CPL 3.6 mW
359 nm 3 min
L-CPL 3.5 mW
359 nm 10 min
L-CPL 2.4 mW
359 nm 30 s
L-CPL 3.5 mW
359 nm 3 min +L-CPL 0.58 mW
510 nm 2 min

Irradiations
R-CPL 1.6 mW
309 nm 5 min
R-CPL 3.6 mW
359 nm 20 min
L-CPL 3.0 mW
359 nm 2 min
R-CPL 320 nm
3 min
R-CPL 359 nm
5 min
R-CPL 1.6 mW
309 nm 5 min
R-CPL 2.5 mW
309 nm 5 min
R-CPL 1.5 mW
280 nm 5 min
R-CPL 2.5 mW
309 nm 5 min
R-CPL 1.3 mW
280 nm 10 min

CD spectra
No signal,
HexaneNo signal,
Hexane(precipitate)
No signal,
HexaneNo signal,
HexaneNo signal,
HexaneNo signal,
HexaneNo signal,
Hexane7 (Photoreaction)
8 (Photoreaction)

R-CPL 280 nm
2.5 h + 5.5 h
L-CPL 280 nm
3.5 h + 4.5 h

CD spectra
No signal,
HexaneNo signal,
HexaneNo signal,
HexaneNo signal,
HexaneNo signal,
HexaneNo signal,
HexaneNo signal,
CHCl3
No signal,
CHCl3
No signal,
CHCl3
No signal,
MeCN(color change)
No signal,
MeCN(color change)
No signal,
MeCN(color change)
Unconverted
reactants
Unconverted
reactants[1] M. Shapiro and P. Brunner, J. Chem. Phys. 95(1991) 8658.

112
Ⅲ03- 2 -Ⅲ -3. Chemistry
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BL3U

Phase Transitions of Liquid-crystal Materials Studied by X-ray Absorption
Spectroscopy
H. Iwayama1,2, H. Yuzawa1 and M. Nagasaka1,2

UVSOR Synchrotron Facility, Institute for Molecular Science, Okazaki 444-8585, Japan
School of Physical Sciences, The Graduate University for Advanced Studies (SOKENDAI), Okazaki 444-8585, Japan
1

2

In addition to gas, liquid and solid phases, liquidcrystal materials have liquid-crystal phase between
solid and liquid phases. In the case of nematic liquidcrystals materials, the rod-shaped organic molecules
have no position order, but they self-align to have longrange directional order with their long axes roughly
parallel. During a phase transition, certain propertiesof materials change, often discontinuously, as a resultof changes of a local chemical environment. Since Xray absorption fine structure (XAFS) spectroscopy issensitive to a local atomic geometry and the chemical
state of the atom of one specific element, XAFS
spectroscopy is suitable to investigate changes ofstructures of materials. In this work, we observe
discontinuous changes of XAFS spectra for liquidcrystal materials.
Our sample is 4-Cyano-4’-pentylbiphenyl (5cb),
which is one of the most popular liquid-crystal
materials. A schematic draw of 5cb molecules is shownin Fig. 1. The phase transition temperature of liquid toliquid-crystal and liquid-crystal to solid are 22.5 and
35 °C, respectively. The XAFS measurements werecarried out at BL3U [1]. After liquid cell which iscomposed of two Si3N4 membranes was filled withthe liquid sample, the thickness of liquid sample was
optimized by controlling the He gas pressure aroundthe cell. The photon energy was calibrated by using theC-K edge XAFS spectrum of the proline thin layer.
Figure 2 shows C K-edge XAFS spectra of 5cb
sample at three different temperature, whichcorrespond to liquid, liquid-crystal and solid phases.
We observed a strong peak at 285 eV, whichcorrespond to a core excitation of C 1s to π* orbitalsof phenyl group. It seems that the peak at 285 eV has
two components, suggesting that π* orbitals of twobenzene rings are different from the viewpoint ofbinding energies. As shown in Fig.2 intensities of thepeak B clearly depend on sample’s phases. To evaluate
relative intensities of peak B, we performed fitting
procedure with using two Gaussian functions.
Figure 3 shows a temperature dependence of peakintensities. We found discontinuous change around
22 °C. This temperature corresponds to the phasetransition temperature between solid and liquid-crystal
phases. During a phase transition between solid andliquid-crystal, sample lose position order. As a results,
local chemical environment change discontinuously. A
more detail analysis is now in progress.

Fig. 1. Schematic draw of 4=Cyano-4’- pentylbiphenl(5cb) molecules.

Ⅲ-3

Fig. 2. C K-edge XAFS spectra of 5cb molecules at
18 (solid), 26 (liquid-crystal) and 39 °C (liquid).

Fig. 3. Temperature dependence of peak B.
[1] M. Nagasaka, H. Yuzawa and N. Kosugi, J. Spectrosc.
Relat. Phenom. 200 (2015) 293.

113
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BL3U

Local Structures of Aqueous Acetonitrile Solutions Probed by Soft X-ray
Absorption Spectroscopy
M. Nagasaka1,2, H. Yuzawa1 and N. Kosugi1,2

Institute for Molecular Science, Myodaiji, Okazaki 444-8585, JapanThe Graduate University for Advanced Studies (SOKENDAI), Myodaiji, Okazaki 444-8585, Japan
1

2

Ⅲ-3

Aqueous acetonitrile solution is one of the most basic
systems showing the microheterogeneity (MH) state,
where two liquids are mixed at macroscopic scale but
are not mixed in microscopic scale [1]. It is necessary toobserve molecular interactions between acetonitrile andwater to discuss the mechanism of the MH state. The
previous studies of infrared spectroscopy and X-ray
diffraction [2] indicate that acetonitrile molecules form
two structures with water: One is hydrogen bond (HB)
between N atom of acetonitrile with H atom of water.
The other is the dipole (DP) interaction between C≡N
group of acetonitrile with water. Recently, Huang et al.
proposed that the population of DP structure is larger
than that of HB structure from O K-edge X-ray
absorption spectroscopy (XAS) [3]. However, O Kedge XAS only gives the molecular interactions fromthe water side. In this study, we have measured XAS ofaqueous acetonitrile solutions at both C and N K-edgesin order to discuss molecular interactions fromacetonitrile side.
The experiments were performed at soft X-ray
beamline BL3U. XAS of liquid samples were measured
by a transmission-type liquid flow cell [4]. The liquid
layers were sandwiched between two 100 nm-thick
Si3N4 and SiC membranes for XAS at C and N K-edges,
respectively. In order to keep the same X-ray
absorbance even at different concentrations, thethickness of the liquid layer was controlled by adjusting
the He pressure around the liquid cell.
Figure 1 shows the energy shifts of the C≡N π* peaks
of aqueous acetonitrile solutions at different
concentrations (CH3CN)x(H2O)1−x from the neat liquid(x = 1.0). In the C K-edge XAS, three concentration
regions are found with the borders of x = 0.7 and x = 0.2.
In the acetonitrile-rich region I (1.0 > x > 0.75), the π*
peaks in C K-edge shows slightly lower energy shifts byincreasing molar fraction of water, and suddenly showsa higher energy shift at x = 0.7. On the other hand, theπ* peaks in N K-edge show higher energy shifts andshow no phase transition-like behavior at x = 0.7. In theregion II (0.7 > x > 0.25), the energy shifts of the π*
peaks in both C and N K-edges are gently increased.
Note that this concentration region shows the MH
behavior [1]. In the water-rich region III (0.2 > x > 0.05),
the slope of the energy shifts in C K-edge is rapidly
increased whereas that in N K-edge is not changed.
We have performed inner-shell calculations ofacetonitrile-water mixtures to discuss local structures ofacetonitrile at different concentrations in terms of theenergy shift in C and N K-edges. As a result, isolated

water molecules disturb the interaction between
acetonitrile molecules in the region I. The acetonitrile
clusters are surrounded by water molecules with the DP
interactions between acetonitrile and water in the region
II. Small acetonitrile clusters form the HB interactions
with water in the HB network of water in the region III.
Since the DP interaction is abundant in the region II, theDP interaction is a key factor to form the MH state inaqueous solutions.

Fig. 1. Energy shifts of the peaks in XAS of aqueous
acetonitrile solutions (CH3CN)x(H2O)1−x relative to thepeak of neat liquid (x = 1.0) at (a) C and (b) N K-edges.
Three concentration regions are found with the bordersof x = 0.7 and x = 0.2.
[1] Y. Marcus, J. Phys. Org. Chem. 25 (2012) 1072.
[2] T. Takamuku et al., J. Phys. Chem. B 102 (1998)
8880.
[3] N. Huang et al., J. Chem. Phys. 135 (2011) 164509.
[4] M. Nagasaka et al., J. Electron Spectrosc. Relat.
Phenom. 224 (2018) 93.

114
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BL3U

Effect of Salt Addition on the Electronic Structure of the Hydrated Water of
Glycine Betaine Studied by Soft X-Ray Absorption Spectroscopy
S. Ohsawa1, N. Fukuda1, H. Iwayama2,3, H. Yuzawa2, M. Nagasaka2,3 and K. Okada1

Graduate School of Science, Hiroshima University, Higashi-Hiroshima 739-8526, Japan
2
Institute for Molecular Science, Okazaki 444-8585, Japan3
School of Physical Sciences, The Graduate University for Advanced Studies (SOKENDAI), Okazaki 444-8585, Japan1

Most living cells adapt to various environments,
such as drought and high salinity, by regulating theconcentration of solutes termed osmolytes [1], because
an increase in extracellular salinity can cause water
efflux and cell shrinkage. Among the most common
organic osmolytes is glycine betaine, which is azwitterionic quaternary ammonium species with pKa =1.84. Its accumulation occurs either by synthesis fromcholine or by transport from extracellular pools [2].
The amount of glycine betaine has been found tocorrelate with external salinity for several shoots ofhalophytes [3] and for halophilic eubacteria [4].
Altering the hydration structure of glycine betaine
with the salt concentration presumably plays animportant role in protecting the secondary structure ofproteins, but the details of interactions of the osmolytewith surrounding water along with salt ions are not yet
fully understood.
Photoabsorption spectra at the oxygen K-edge were
measured in the transmission mode at room
temperature. Aqueous solutions of glycine betaine,
sodium chloride, and mixed glycine betaine andsodium chloride were introduced with a tubing pumpsystem into a liquid flow cell installed on the soft Xray beamline BL3U. The flow cell for this study was
equipped with a pair of windows made of thin silicon
nitride membrane. Further details of the cell were
given elsewhere [5]. The incident photon energy wascalibrated to the peak at 530.88 eV of a polymer film
[6].
The measured absorption spectra vary from solution
to solution. Figure 1 displays the O 1s absorption
spectra of glycine betaine, sodium chloride, theirmixed aqueous solutions, and liquid water. The broken
vertical line corresponds to the resonance energy of the
4a1 ← O 1s transition of bulk water located at 534.6
eV. For solutions containing glycine betaine, anotherbroad peak appears around 532.2 eV. Because its
intensity depends on the osmolyte concentration, thepeak is safely assigned to π*COO ← O 1s of glycine
betaine.
The resonance peak top of water is shifted by −0.05
and +0.09 eV for glycine betaine and sodium chloride
solutions, respectively. The shift is caused by thechange of chemical environment around water. The
red shift seen for the glycine betaine solution can be
ascribed to the gain of partial negative charge on theoxygen atom of water by making a strong hydrogenbond with the carboxylate site of glycine betaine.
For the mixed aqueous solutions, an apparent blue
shift can be seen for the spectra of samples with thesalt concentration greater than or equal to the osmolyte
concentration. This observation can be described by
the interpretation that the salt is exclusively bound toglycine betaine, and thereby reveals the role of theosmolyte when living cells are exposed to salinity.

Ⅲ-3

Fig. 1. Enlarged O 1s photoabsorption spectra in the
530–536 eV region of glycine betaine (Bet), sodium
chloride, their mixed aqueous solutions, and liquidwater. The concentration of each solute is 1.0 mol/L.
[1] P. H. Yancey, M. E. Clark, S. C. Hand, R. D. Bowlus
and G. N. Somero, Science 217 (1982) 1214.
[2] L. N. Csonka, Microbiol. Rev. 53 (1989) 121.
[3] R. Storey and R. G. Wyn Jones, Plant Sci. Lett. 4(1975) 161.
[4] J. F. Imhoff and F. Rodriguez-Valera, J. Bacteriol.
160 (1984) 478.
[5] M. Nagasaka, T. Hatsui, T. Horigome, Y. Hamamura
and N. Kosugi, J. Elec. Spectrosc. Relat. Phenom. 177(2010) 130.
[6] M. Nagasaka, H. Yuzawa, T. Horigome and N.
Kosugi, J. Elec. Spectrosc. Relat. Phenom. 224 (2018) 93.

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BL3U

X-ray Absorption Measurements Applied to Aqueous Solutions of Glycine
at Various pHs, in the Vicinity of the O K-edge Ionization Thresholds
D. Céolin1, T. Saisopa2, K. Klaiphet2, P. Songsiriritthigul2, H. Yuzawa3, M. Nagasaka4 andN. Kosugi4,5

2

Ⅲ-3

1
Synchrotron SOLEIL, L'Orme des Merisiers Saint-Aubin BP 48 91192 Gif-sur-Yvette Cedex, France
Research Network NANOTECH-SUT on Advanced Nanomaterials and Characterization and School of Physics,
Suranaree University of Technology, Nakhon Ratchasima 30000, Thailand
3
UVSOR Synchrotron Facility, Institute for Molecular Science, Okazaki 444-8585, Japan
4
Institute for Molecular Science, Okazaki 444-8585, Japan
5
Institute of Materials Structure Science, KEK, Tsukuba 305-0801, Japan

Glycine, the simplest amino acid, is involved in avariety of physiological processes, such as e.g.
neurotransmitter in the central nervous system, and iscommonly found as a protein precursor. Gas-phaseglycine has a neutral form H2N-CH2-COOH whereas
in aqueous solution its structure differs depending on
the pH. For pH in the range 2.4-9.6, the zwitterionicform +H3N-CH2-COO- dominates. In acidic medium
below pH = 2.4, the protonated form +H3N-CH2COOH is the main one, whereas in basic medium
above pH = 9.6, the deprotonated form H2N-CH2COO- prevails (see Fig. 1).
Among our measurements performed at thebeamline BL3U using the liquid cell in transmissionmode, we obtained the absorption spectra of glycine inaqueous solution at different pH, at a concentration of
0.5 M, and in the vicinity of the O K-edge ionizationthreshold (see Fig. 2). The idea was to collect spectra
in a larger energy window than in the reference [1].
The resonance located at hν = 535 eV is associatedwith the oxygen 1s electron excitation of water to its
first empty orbital. On the left side of this structure, we
confirm the presence of smaller resonances attributed
to the excitation of an oxygen 1s electron of the
carboxyl/carboxylate groups of solvated glycine. The
O1s* excitation of –COO- leads to a maximum
located at 532.75 eV, whereas for –COOH the
maximum is found at 532.45 eV. For this latter, only
the transition involving the C=O group is visible. The
one corresponding to the –OH excitation is located ata photon energy close to the one of water and is thus
not detected in our spectra.
Contrary to the observations presented in reference[1], due to a reduced statistic, we do not highlight aclear asymmetry of the low energy resonance in theacidic solution. However, we can extract some
additional information such as the –COO-/–COOH
O1s* widths (Gaussian FWHM): 0.85 eV for pH =1, 1.21 eV for pH = 7 and 1.25 eV for pH = 12, and thecorresponding relative areas: 0.52 for pH = 1,
normalized to 1 for pH = 7, and 0.77 for pH = 12.
Considering that the –OH part of the carboxylic groupdo not resonate in this photon energy region, the lower
intensity of the 1st structure for the acidic solution is

not surprising. Furthermore, the larger contribution of
the same resonances for the two other solutions is dueto the possibility of exciting two oxygens instead of
only one. Also, the overlap with the 2nd large resonancehaving a maximum at 535 eV increases the uncertaintyof the areas estimate especially for the solutions at pH= 7 and 12 since they are located closer in photon
energy.

Fig. 1. Structure of glycine in aqueous solution forvarious pH regions (acidic, neutral, basic).

Fig. 2. Normalized X-ray absorption spectra ofsolvated glycine, recorded for various solutions pH.
[1] B. M. Messer, C. D. Cappa, J. D. Smith, K. R.
Wilson, M. K. Gilles, R. C. Cohen and R. J. Saykally,
J. Phys. Chem. B 109 (2005) 5375.
[2] M. L. Gordon, G. Cooper, C. Morin, T. Araki, C. C.
Turci, K. Kaznatcheev and A. P. Hitchcock, J. Phys.
Chem. A 107 (2003) 6144.

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BL3U

In situ O K-edge X-ray Absorption Spectrum Study of a-Si/SEI in
Photocatalytic Water Splitting
1

J. Ma1, H. Yuzawa2, H. Ju1 and R. Long1

Hefei National Laboratory for Physical Sciences at the Microscale, iChEM (Collaborative Innovation Centerof Chemistry for Energy Materials), School of Chemistry and Materials Science, and National Synchrotron
Radiation Laboratory, University of Science and Technology of China, Hefei, Anhui 230026, China
2
UVSOR Synchrotron Facility, Institute for Molecular Science, Okazaki 444-8585, Japan

Amorphous Si/SEI (a-Si/SEI) nanowire arrays was
fabricated and both activity and durability of siliconmaterial for photocatalytic water splitting can bedramatically enhanced. The Si nanoarrays were first
loaded in a battery cell, then facilely engineered into
active and durable structures, during which lithiation
amorphizes silicon and forms a surface protection
layer. The photocatalytic hydrogen production was
conducted to assess the performance of the as
fabricated Si NWs for photocatalytic hydrogenproduction in ultrapure water. Remarkably, theprocessed silicon nanowire arrays achieve an apparent
quantum efficiency (AQE) of 1.74% in pure water
under 450 nm light irradiation with excellent durability.
The lithiated Si NWs achieved a hydrogen production
rate of 6.0 μmol∙h-1 at the first reaction cycle. However,hydrogen production rate was reduced to 3.4 μmol∙h-1
in the second reaction cycle and became stable
thereafter as indicated by the next 50 h of test.
Then the X-ray photoelectron spectroscopy (XPS) was
conducted to characterize surface of the discharged Si
NWs which plays a significant role in the photocatalytichydrogen production. As revealed in Fig. 1, the Si NWs
samples before reaction (a), after reaction 4 h (b) and 20
h (c) radiation were measured by in-house XPS.
We can observe the Si at 99 eV binding energy
assigned to bulk amorphous silicon, the peak at 103 eV
binding energy assigned to surface oxide SiO2, the peakat ~101.5 eV binding energy assigned to the lithium
orthosilicate Li4SiO4 and the peak at ~105 eV binding
energy assigned to the partially fluorinated compoundSiOxFy located at the extreme surface. The relative
intensity of the partially fluorinated compound SiOxFy
became weaker. And the relative intensity of other Si
species changes dramatically after photocatalytic
reaction. Indeed the bulk amorphous silicon species
relative intensity has significant increase after
photocatalytic reaction and stay almost unchanged as
the photocatalytic reaction goes on which can be
attributed to the change of LiF in solid electrolyte
interphase (SEI) during the photocatalytic reaction, andthe partially fluorinated compound SiOxFy species
relative intensity obviously weakens at the begin of thereaction and then keeps constant while the relative
intensity of the surface oxide SiO2 and the lithium
orthosilicate Li4SiO4 appears no obvious change during
the reaction.
To further observe the evolution of the surface

condition during the photocatalytic reaction, the in situ
near edge X-ray absorption fine structure (NEXAFS)
was conducted at UVSOR Synchrotron Facility. As
shown in Fig. 2, the in situ O K-edge XAS wascollected before and after illumination in the chamber.
We can see that peaks of SiO2, Li4SiO4 and SiOxFy
from the spectra. However, the peaks of SiOxFy
obviously became weaker assigned to reduction ofcontent, which can is consistent with the X-ray
photoelectron spectroscopy. And the peak of Li4SiO4almost disappeared after illumination owing to themeager content Li4SiO4 and weak signal. Overall, theintensity of SiOxFy decreases significantly at thereaction starting indicating reduction of SiOxFy which
we think can well explain the drop of photocatalytichydrogen production rate at first cycle. The otherspecies remain basically unchanged and these species
can reasonably protect the innermost amorphous fromphotocorrosion.

Fig. 1. XPS spectra evolution during reaction.

Fig. 2. In situ O K-edge X-ray absorption spectra.

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Ⅲ03- 7 -Ⅲ-3

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BL3U

Mechanistic Investigation of Homogeneous Iron-Catalyzed Organic
Reactions based on Solution-Phase L-edge XAS
H. Takaya1, M. Nagasaka2 and K. Kashimura3

International Research Center for Elements Science, Institute for Chemical Research, Kyoto University,
Uji 611-0011, Japan
2
UVSOR Synchrotron Facility, Institute for Molecular Science, Okazaki 444-8585, Japan
3
Faculty of Engineering, Chubu University, Kasugai 487-8501, Japan1

Ⅲ-3

We have found that iron complexes of FeX2SciOPP(X = Cl, Br) bearing bulky phosphine ligand SciOPP
showed excellent catalytic activities toward the crosscoupling of organometallic reagents of Mg, B, Al, andZn with various aryl halides (Eq. 1) [1, 2]. Such ironbased catalysts for organic reactions alternative to theconventional precious metal catalysts has been
intensively investigated for the development of futuresustainable chemical processes. Solution-phase XAS
analysis is highly useful for the mechanistic study ofiron-catalyzed organic reactions to identify thecatalytically active organoiron species with theirelectronic and molecular structures, because theconventional solution-phase NMR-based analysis
cannot be used due to the paramagnetic nature oforganoiron species along with the large paramagnetic
shift and peak broadening in NMR spectrum. L-edge
XAS of transition-metal catalysts has been expected tobe highly useful to investigate the electronic structure of
3d orbitals which provide an essential information to
elucidate how to work the catalyst. However, solutionphase L-edge XAS measurement is generally difficult
because the measurement has to be performed under
low-pressure vacuum condition where the solution
sample is evaporated with vigorous boiling. In thisproject, we used the specially designed flow-cell for thesolution-phase L-edge XAS measurement ofhomogeneous organic solution of iron complex catalysts.
In BL3U beamline, a stainless-steel flow cell has beenused for various experiments, but we should carefully
avoid contamination of iron species from theenvironment. For this reason Prof. Nagasaka newly
designed and prepared PEEK-made flow cell bearing
ultra-thin 100 nm Si3N4 membrane X-ray window asshown in Fig. 1. The solvent-resistant PEEK made bodyshows an excellent chemical resistance toward thevarious organic solvents such as THF, CH2Cl2, andbenzene, these often used in iron-catalyzed cross-coupling reactions. This flow cell was introduced into
the helium-filled chamber which inserted to the X-ray
optics line, and connected to syringe pump through a
Teflon tube. The THF solution sample of FeCl2SciOPP
was prepared in an argon-filled glovebox, because thistype of iron complex in solution is quite sensitive tooxygen and water, and immediately react to give ironoxide and hydroxide. The L-edge XAS experiment was
carried out both stop and flow (flow rate: 50 – 500 μL/h)
conditions to validate the XAS stabilities, base line
moving, S/N change etc. As a result, a serious spectrum
change and base line jump randomly occurred tointerfere the stable XAS measurement by penetration ofhelium gas in chamber into the cell and made a bubble
inside the sample space to cut across X-ray beam. To
solve this problem, the Viton O-ring is changed to afluorosilicone polymer with improving the flow line
design and tube connection. This improved cell will betested in the next experiment scheduled in 2019.

Fig. 1. Photo of the PEEK-made flow.
[1] H. Takaya and M. Nakamura et al., Bull. Chem.
Soc. Jpn. 88 (2015) 410.
[2] R. Takaya and M. Nakamura et al., Bull. Chem.
Soc. Jpn. 92 (2019) 381.

118
Ⅲ03- 8 -Ⅲ -3. Chemistry
BL3U
BL3U

Electronic Structures of Carbon Dots in Aqueous Dispersions Probed byin-situ Transmission X-ray Absorption Spectroscopy
J. Ren1, D. S. Achilleos2, E. Reisner2 and T. Petit1

Institute of Methods for Material Development, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH,
Albert-Einstein-Strasse 15, 12489 Berlin, Germany
2
Christian Doppler Laboratory for Sustainable SynGas Chemistry, Department of Chemistry, University ofCambridge, Lensfield Road, Cambridge CB2 1EW, UK

1

Carbon dots (CDs) are promising photocatalysts for
artificial photosynthesis since they are (1) inexpensive
and non-toxic, (2) chemically and photochemicallyrobust, (3) show good water solubility and (4)controlled photocatalytic properties upon predesigned synthesis. Recently, we reported a facile
method to prepare CDs of controlled nanostructuresand elemental compositions by varying the organic
precursors and the calcination temperatures employed
for the synthesis. This approach allows the synthesisof graphitic CDs with (g-N-CDs) and without (g-CDs)core nitrogen doping, as well as amorphous CDs (aCDs), which all show very distinctive photocatalytic
properties.[1]During this beamtime, colloidal dispersions of thesethree CDs were successfully characterized by soft Xray absorption spectroscopy (XAS) at different
concentrations. Both the carbon and oxygen K edges
were characterized to monitor the impact of hydrationon the electronic structure of both CDs and watermolecules. Furthermore, these measurements werecompared to XAS performed in total electron yield in
vacuum and total ionic yield in liquid at BESSY II
synchrotron, Germany.
XAS at the C K edge demonstrates that the core of
the CDs is poorly influenced by the aqueous dispersion.
On the other hand, electronic states associated with CO bonds from surface groups appear enhanced indispersion, which is attributed to the formation ofhydrogen bonds with water molecules in theirsolvation shell.
At the O K edge, the signature of the CDs surface
groups is screened by the contribution from watermolecules (Fig. 1). However, strong changes on thewater signature, composed of a pre-, main- and postedges were found to depend on CDs as well as
concentration. We previously observed similarchanges in nanodiamonds colloidal dispersions andattributed them to strong changes of the waterhydrogen bond network induced by the nanoparticles
hydration.[2] These new results suggest that CDs alsosignificantly interact with water molecules in theirsolvation shells.
These results are the first demonstration that carbon
dots interact strongly with their hydration shell and thefirst in situ XAS characterization of CDs. Based onthese results, an article has recently been submitted for
publication.

Ⅲ-3

Fig. 1. Transmission mode XA spectra at O K-edge
from (a) water and different CDs dispersions (8 wt%)and (b) a-CD, (c) g-CD, (d) g-N-CD at different
concentrations. The pre/main-edge ratios for each
spectrum are plotted below XA spectra.
[1] B. C. M. Martindale, G. A. M. Hutton, C. A. Caputo,
S. Prantl, R. Godin, J. R. Durrant and E. Reisner, Angew.
Chemie Int. Ed. 56 (2017) 6459.
[2] T. Petit, H. Yuzawa, M. Nagasaka, R. Yamanoi, E.
Osawa, N. Kosugi and E. F. Aziz, J. Phys. Chem. Lett.
6 (2015) 2909.

119
Ⅲ03- 9 -Ⅲ -3. Chemistry
BL4U
BL4U

P-L2,3 Absorption Spectra of Phosphates in Plasmid DNA and Cell Nucleus
T. Ejima1, M. Kado2, T. Ohigashi3 and S. Tone4IMRAM, Tohoku University, Sendai 980-8577, Japan
Takasaki Adv. Rad. Res. Inst., QST, Takasaki 370-1292, Japan
3
UVSOR Synchrotron Facility, Institute for Molecular Science, Okazaki 444-8585, Japan
4
Sch. of Sci & Technol., Tokyo Denki University, Hatoyama 350-0394, Japan
1

2

Ⅲ-3

Phosphate PO43− plays a major role in the structural
framework of DNA and RNA. DNA in living cells is
mainly present in cell nuclei, and phosphate PO43− iscontained in DNA, RNA, and some phosphorated
proteins among the constituent molecules of cell
nuclei [1]. On the other hand, DNA exists alone inbacteria and yeast, and this DNA, called plasmid DNA,is present in the cytoplasm and replicates itself
autonomously and independently of genomic DNA [2].
The phosphate PO43− forms ideally a tetrahedral
structure in which four oxygen atoms coordinate
equidistantly with a P atom as the center. The
absorption spectrum excited at the P-L2,3 absorption
edge shows an electronic structure reflecting the s or d
orbitals of the P atoms by the dipolar transition.
Furthermore, if the chemical bonding states of amaterial is changed, the energy position of absorption
edge will shift. In this study, the electronic structures
and the chemical bonding states of the phosphate arecompared by the P-L2,3 absorption edge structures
between the cell nucleus and the plasmid DNA.
As measurement samples, plasmid DNA extracted
from E. coli and cell nuclei separated from Hela cells
were dispersed in TE solutions, and the solutions of
0.5 μL each were dropped on 50 nm thick SiN
membranes and then air-dried as it were. X-ray
absorption measurements were performed using
STXM beamline of BL4U under the experimental
conditions: energy resolution E / δE = 1000, andspatial resolution 50 nm, and under He atmosphere.
The obtained spectra are shown in Fig. 1.
The spectral intensity of plasmid DNA increases
sharply at around 133 eV, and structures observed are
indicated as Peak A ~ D in the figure. Peak intensity
increases from Peak A to Peak D and decreases
gradually on the higher energy side of Peak D (Fig. 1(a)). The spectrum shape of the normal cell nucleus
likes that of the plasmid DNA, but no explicit peakstructures can be seen corresponding to Peak A~ D
observed in the plasmid DNA (Fig. 1 (b)). A broad
structure is observed (Peak E) with a broad shoulder
structure (Peak F). In the plasmid DNA spectrum,
spectral intensities of Peak E and F are weak, and thespectral shape looks as a part of the tail of Peak D.
The similar structures of the spectral shapes can berecognized by the tetrahedral coordination of thephosphate PO43− in DNA [3]. The different structures
will be due to the phosphate PO43− of the protein
molecules other than DNA in the cell nucleus.

Fig. 1. P-L2,3 X-ray absorption spectrum of plasmidDNA, (a), and of normal cell nucleus (b). Dots
represent the measurement results, curves are 5 pointsmoothing results of the measurement points for guideto see. Both spectra are normalized by the maximum
peak height around 145 eV.
[1] K. Shinohara, S. Toné, T. Ejima, T. Ohigashi and A.
Ito, Cells 16 (2019) 164.
[2] for example, K. Akasaka and Y. Ohyama,"Principle of Gene Technology", (Syoukabo Co. Ltd.,
2013, Tokyo, ISBN 978-4-7853-5856-3 C3045).
[3] S. O. Kucheyev, C. Bostedt, T. van Buuren, T. M.
Willey, T. A. Land, L. J. Terminello, T. E. Felter, A. V.
Hamza, S. G. Demos and A. J. Nelson, Phys. Rev. B
70 (2004) 245106.

120
Ⅲ03- 10 -Ⅲ -3. Chemistry
BL4U
BL4U

Heterogeneous Network Structure in Natural Rubber
1

Y. Higaki1 and A. Takahara2

Department of Integrated Science and Technology, Faculty of Science and Technology, Oita University,
Oita 870-1192, Japan
2
Institute for Materials Chemistry and Engineering, Kyushu University, Fukuoka 819-0395, Japan

Natural rubber (NR) latex is a liquid rubber productapplied for thin rubber sheets and adhesives. The NR
latex is a colloid of NR particles dispersed in serum
including proteins, lipids, inorganic salts[1]. NR
particles consist of a spherical core of poly(cis-1,4isoprene) and outer shell membrane of a protein-lipid
monolayer of approximately 20 nm thickness. The
stable dispersion of NR particles is encouraged by thenegatively charged substances covered on the surface.
Because the NR sheets are produced by the coagulationof the NR particles involving protein and/or lipid shell,
the NR sheets would exhibit heterogeneous networkwith boundary consisting of protein and lipids. In
addition, the network structure through C-S, C-S-S
bonds produced by vulcanization would be hardly
uniform in the rubber matrix. We tried to address theheterogeneous chemical structure distribution in the NR
sheets by cross-sectional chemical imaging of the NR
sheets by means of scanning transmission X-ray
microscopy (STXM) with soft X-ray.
NR particles, of which the averaged particle size isapproximately 200 nm, were introduced into a glass dishthen dried up subsequently vulcanized with sulfur to
produce a vulcanized natural rubber sheet (thickness: 500μm). The NR sheet was trimmed without embedding inresin by ultramicrotome to prepare ultra-thin film (setting
thickness: 100 nm). The thin films were mounted on acopper grid without collodion supporting membrane(Ohken, Cu 100-A).
STXM experiments were performed at the 4U
beamline equipped with a Fresnel zone plate beamfocusing apparatus and a R647P photomultiplier tube
detector with a P43 scintillator. The dwell time and thescanning pitch were 2 msec and 0.2 μm step, respectively.
A typical STXM image of the cross-section thin filmof the vulcanized natural rubber sheet at 285.2 eV isshown in Fig. 1 (a). Heterogeneous morphology withrandom domain network was observed. The average
domain diameter was approximately 1 μm. The C1s
STXM spectra exhibits a sharp absorption peak at 285.2
eV and a broad absorption at 288 eV (Fig. 1 (b)). The
absorptions are attributed to C-Hπ* signals fromunsaturated C-C double bonds in poly(cis-1,4isoprene)[2]. Because the base line absorption is even,
the OD contrast would be attributed to the density
inhomogeneity nor the uneven thickness. The C-Hπ*
signals in the domains was stronger than that ofcontinuous matrix region. The NR particles would
intrinsically involve radial density inhomogeneity.
Meanwhile, the protein and lipids in the original NR

latex particles accumulate at the particle boundary
leading to the reduction of poly(cis-1,4-isoprene)
density in the boundary. The NR particles coalesce in
the NR sheet production process to produce the low
density continuous network, however, the particle cores
would remain without fusion to yield the high density
domain regions.
As shown in the above results, we successfully
unraveled the density heterogeneity in the NR bulk bymeans of STXM imaging.

Ⅲ-3

Fig. 1. Cross section of natural rubber sheet. (a)STXM micrograph (10 x 10 mm) at 285.2 eV. (b) C1s
absorption spectra of the dark domains (red) and brightmatrix (green) regions.
[1] S. Kumarn, N. Churinthorn, A. Nimpaiboon, M.
Sriring, C. C. Ho, A. Takahara and J. Sakdapipanich,Langmuir 34 (2018) 12730.
[2] S. G. Urquhart, A. P. Hitchcock, A. P. Smith, H. W.
Ade, W. Lidy, E. G. Rightor and G. E. Mitchell, J.
Electron Spectros. Relat. Phenom. 100 (1999) 119.

121
Ⅲ03- 11 -Ⅲ -3. Chemistry
BL4B
BL4B

Multi-electron–Ion Coincidence Spectroscopy Applied to Metastability of
Carbonyl Sulfide Dications
Institute of Liberal Arts and Sciences, University of Toyama, Toyama 930-0194, Japan
2
Institute for Molecular Science, Okazaki 444-8585 Japan

Time-of-flight of ion (s)
8

10

12

14

OCS2+

1500
1000

C+

S+
+

O /S

2+

500

CO+

0

Intensity (arb. units)
5000
10000

45

45

40

40

35

80

35

60
40

30

20

30

0

8

Binding energy of OCS2+ (eV)

Carbonyl sulfide is one of the molecules whose
dications are known to be stable in the μs regime. A
theoretical calculation predicted that many OCS2+
electronic states have potential energy surfaces withlocal minima [1]. In practice, high-resolution Auger
spectroscopy [2] and photoelectron-photoelectron
coincidence spectroscopy [1,3] have revealed thevibrational structures of several electronic states in
OCS2+. Kaneyasu et al. have already investigated themetastability and fragmentation of the OCS2+ states byAuger electron-ion coincidence spectroscopy [4].
However, overlapping Auger structures from thedifferent S2p core-hole states, as well as the moderateenergy resolution, obscures the metastability of
individual electronic states. In this study, we applied
multi-electron-ion coincidence spectroscopy to the S2p
Auger decay in OCS and revealed the metastability ofeach electronic state [5].
The two-dimensional map in Fig. 1 shows
correlations between the OCS2+ dication states andtimes-of-flight of ions, derived from the triple
coincidences among S2p photoelectron, Auger electron,and ion. On this map, coincidence with OCS2+ ion isremarkably seen for the low-lying dication states arounda binding energy of 32 eV. On the other hand,formations of fragment ions are remarkable above abinding energy of 35 eV. These observations basicallyconfirm the findings by Auger electron-ion coincidence
spectroscopy [4].
The band around a binding energy of 32 eV consistof three dication states (X3Σ-, a1Δ and b1Σ+) resulting
from the removals of two electrons from the 3π orbitals.
A closer inspection on the coincidence yields reveals
that only the highest-lying b1Σ+ state dissociates intofragments in the μs regime, though the fraction of the
dissociation path is very weak. The calculated potential
energy surfaces of these three states have all deep wells,
and efficient tunneling dissociation only for the b1Σ+
state is not likely. The potential energy curve of the b1Σ+
state along CS stretch intersects that of the 11Π state [1].
The dissociation of the b1Σ+ state in the μs regime
possibly results from the conversion into the 11Π state.
Since the crossing point of the two potential energy
curves locates around 2 eV above the potential minimaof the b1Σ+ state [1], the heterogeneous predissociation
should be extremely inefficient and thus proceeds in theμs regime.

Intensity (arb. units)

Ⅲ-3

Y. Hikosaka1 and E. Shigemasa2

Binding energy of OCS2+ (eV)

1

10

12

14

Time-of-flight of ion (s)Fig. 1. Two dimensional map showing correlations
between the OCS dication states (right panel) andtime-of-flights of ions (top panel), derived from thetriple coincidences among S2p photoelectron, Auger
electron, and ion.
[1] V. Brites, J. H. D. Eland and M. Hochlaf, Chem.
Phys. 346 (2008) 23.
[2] V. Sekushin, R. Püttner, R. F. Fink, M. Martins, Y.
H. Jiang, H. Aksela, S. Aksela and G. Kaindl, J. Chem.
Phys. 137 (2012) 044310.
[3] J. H. D. Eland, Chem. Phys. 294 (2003) 171.
[4] T. Kaneyasu, M. Ito, Y. Hikosaka and E. Shigemasa,
J. Korean Phys. Soc. 54 (2009) 371.
[5] Y. Hikosaka and E. Shiegemasa, Int. J. Mass
Spectrom. 439 (2019) 13.

122
Ⅲ03- 12 -Ⅲ -3. Chemistry
BL4B
BL4B

Pulsed Electron Extraction Introduced into a Magnetic Bottle
Time-of-flight Electron Spectrometer
Y. Hikosaka

Institute of Liberal Arts and Sciences, University of Toyama, Toyama 930-0194, Japan
electrons emitted on the formation of high-lying Xe+
states and on their subsequent decay. Weak cyclic
peaks, which are noticeable in the region of >800 ns,
are due to the valence photoionization by the secondorder light. The emitted 5p photoelectrons have alarger kinetic energy than the retardation voltage, andthus the detections cannot be precluded.

Conventional way

100000

15000
80000

Ⅲ-3
10000
60000

CountsMulti-electron coincidence spectroscopy using amagnetic bottle time-of-flight electron spectrometer [1]is one of the most powerful means to study the multielectron emission processes of atoms and molecules.
The magnetic bottle electron spectrometer captureselectrons over 4π-sr. solid angle by utilizing themagnetic mirror effect, and the electron energy analysis
is based on electron time-of-flight measurement. A
pulsed light source is thus required for the use of amagnetic bottle spectrometer. The single-bunch
operations of synchrotron storage rings provide lightpulses applicable to the electron time-of-flightmeasurement. However, the circumference of the usedstorage ring limits the periodicity of the light pulses(178 ns for the UVSOR-III ring), and the periodicity is
usually shorter than the times-of-flight of slow electrons
measured with a magnetic bottle electron spectrometerof a-few-meter length. For example, the single bunch
operation of the UVSOR-III ring provide light pulses
with periodicities of 178 ns, while a slow electron (<1eV) takes several μs for a-few-meter flight.
In this work, a novel method to measure long electron
time-of-flight with short-cycle light pulses isestablished [2]. In the method, a virtual stretch of lightpulse intervals is achieved by pulsed extraction ofelectrons. Here, the observations of electrons are mostly
precluded by a DC retardation electric field and are
periodically allowed by applying negative voltage
pulses to drop the potential at the electron source region.
The performance of the pulsed extraction method
was evaluated by measuring electrons emitted fromthe Xe 4d5/2-16p resonance at a photon energy of
65.110 eV. Figure 1 shows the time-of-flight spectrumof all the electrons measured with the pulsed extraction
method, compared with that by the conventional way(no extraction pulse and no retardation voltage). On
the measurement by the pulsed extraction, the negative
voltage pulses of -70 eV were applied to the electrodes,
under a DC retardation voltage of -70.0 V. The
spectrum obtained by the conventional way exhibits
cyclic structures resulting from the 178-ns repetitionof light pulses. Severe overlaps of slow electrons
construct the large background structure lying below
the sharp peaks. In contrast, the overlaps are
effectively removed in the spectrum measured with thepulsed extraction method, where the absolute timesof-flight of the electrons are determined. Sharp peaks
in 300-450 ns result mainly from the spectator Auger
decays of Xe 4d5/2-16p into Xe+ 5p-26p, and the broad
structure centered at around 500 ns contains slower

5000

40000

0

20000

Pulsed extraction

0

500

1000

1500

0

Time-of-flight of electron (ns)Fig. 1. Time-of-flight spectra of all electrons emitted
from Xe at the photon energy for the 4d5/2-16p
resonance (65.110 eV), with the conventional way (inblack) and the pulsed extraction method (in red).
[1] J. H. D. Eland, O. Vieuxmaire, T. Kinugawa, P.
Lablanquie, R. I. Hall and F. Penent, Phys. Rev. Lett.
90 (2003) 053003.
[2] Y. Hikosaka, in preparation.

123
Ⅲ03- 13 -Ⅲ -3. Chemistry
BL4B
BL4B

Double Auger Decay from the Xe 4d5/2-16p Resonance Studied byMultielectron Coincidence Spectroscopy
Y. Hikosaka

Institute of Liberal Arts and Sciences, University of Toyama, Toyama 930-0194, Japan
formations. The intensities of the spots imply that the 5s5p-1(1P)6p state decays with a similar intensity into the3
P2, 3P0,1 and 1D2 final states, but much weakly into the1
S0 state. The preference in the decay channels differs
among different 5p-35d6p states.
1

Kinetic energy of fast electron (eV)
5

10

15

20

25

30

-2 1

5s ( S)6p

10000

5p-35d6p
5s-15p-1(1P)6p

5000

Counts05p-2 318

Kinetic energy of slow electron (eV)Ⅲ-3

Auger decay is the main decay pathway from innershell excited states in light atoms, where two Auger
electrons are ejected with a sizable probability. Multielectron coincidence spectroscopy using a magnetic
bottle time-of-flight electron spectrometer is a powerfulmeans to investigate the double Auger decay
mechanism. In this work, the double Auger decay of theXe 4d5/2-16p resonance is studied with multielectron
coincidence spectroscopy [1].
Figure 1 shows the coincidences of the two Auger
electrons emitted in the resonant double Auger decay. In
the two-dimensional map, the formation of individual
Xe2+ states by the direct path in the resonant double
Auger decay appear as diagonal stripes. This is because
the two Auger electrons simultaneously emitted sharecontinuously the available energy which corresponds tothe energy difference between the initial Xe 4d5/2-16p
state and a final Xe2+ state. The locations of the diagonal
stripes for the formations of the Xe2+ 5p-2 and 5s-15p-1
states are indicated on the two-dimensional map.
Intense spots are exhibited on these diagonal stripes.
The cascade path in the resonant double Auger decay
produces these spots, where the coordinates of the spots
are defined by the discrete kinetic energies of the twoAuger electrons. For most spots, the fast electrons are
emitted in the first-step decay into Xe+ states lying
above the Xe2+ threshold, and the slow electrons areejected in the subsequent decay of the Xe+ states into
low-lying Xe2+ states.
The projection of the coincidence counts in the twodimensional map onto the horizontal axis is potted in the
top panel of Fig. 1. The projection spectrum delineatesthe structure of the Xe+ states formed intermediately inthe cascade path. These Xe+ structures have been
revealed by conventional Auger spectroscopy in somemore detail [2]. The sharp peaks lying around 13 eV and
24 eV are assigned to 5s-2(1S)6p and 5s-15p-1(1P)6p,
respectively, where the excited electron behaved as aspectator on the Auger electron emission. The structurearound 20 eV consists of many Xe+ states whose
dominant configuration is 5p-35d6p. While conventional
Auger spectroscopy locates also the second-step Augertransitions from these intermediate Xe+ states into final
Xe2+ states [2], more unambiguous identifications of thecascade pathways can be made from the features on thetwo-dimensional map. The decays from 5s-15p-1(1P)6p
and 5s-35d6p into Xe2+ 5p-2 states are exhibited as intense
spots lying on the diagonal stripes for the final Xe2+

P
P0,1 2
D2

1

16

1

S0

14

320

12
10
8

3

3

P0,1,2-1

5s 5p-1
1

240

P1

160

6

80

4
2
5

10

15

20

25

30

0

Kinetic energy of fast electron (eV)Fig. 1. Energy correlation map between two Auger
electrons emitted in the resonant Auger decay from the
4d5/2-16p resonance in Xe. The projection of thecoincidence counts in the two-dimensional map onto
the horizontal axis is shown in the top panel. The
structures seen in the projection spectrum depict theXe+ states formed intermediately in the cascade pathof the resonant double Auger decay.
[1] Y. Hikosaka, in preparation.
[2] S. Osmekhin et al., J. Electron Spectrosc. Relat.
Phenom. 161 (2007) 105, and references therein.

124
Ⅲ03- 14 -Ⅲ -3. Chemistry
BL4B
BL4B

Critical Absorbed Dose of Resinous Adhesive Material Towards NonDestructive Chemical-State Analysis Using Soft X-Rays
H. Yamane1, M. Oura1, N. Yamazaki2, K. Hasegawa3, K. Takagi4 and T. Hatsui1

RIKEN SPring-8 Center, Sayo 679-5148, Japan
Research & Innovation Center, Mitsubishi Heavy Industries, Ltd., Yokohama 220-8401, Japan
3
Research & Innovation Center, Mitsubishi Heavy Industries, Ltd., Nagoya 455-8515, Japan
4
Fixed Wing Aircraft Engineering Department, Mitsubishi Heavy Industries, Ltd., Toyoyama 480-0202, Japan
1

2

Epoxy resins are the most common matrix materials
for high-performance composites and adhesives.
Tetraglycidyl-4,4’-diaminodiphenylmethane cured by
4,4’-diaminodiphenylsulfone (TGDDM-DDS) is anarchetypal model material for the adhesive bonding.
Because the oxygen element plays a crucial role in thechemical interaction and the resultant bonding strength
at adhesive interfaces, the O K-edge X-ray absorption
spectroscopy (XAS) is one of reliable techniques tounderstand the chemical interaction at adhesiveinterfaces. In this work, we performed the quantitative
examination of the radiation damage on TGDDM-DDS
for the precise analysis of the local chemical state using
soft X-rays.
The total-electron-yield (TEY) XAS experiment was
performed at BL4B. In the present work, the resolving
power (hv/ΔE) at hv = 500 eV, the photon flux (Nph), andthe photon spot size at the surface (S) were 2500, 6×109
ph/s and 0.847 mm2, respectively. The TGDDM-DDS
was obtained by the curing reaction after stirring theuncured TGDDM with the DDS curing agent. To avoid
the charging effect in TEY-XAS, we made theconductive path between the sample surface and theground by pasting the Al- covered carbon tape nearby
the measurement spot.
Figure 1 shows the O K-edge TEY-XAS spectra for
TGDDM-DDS at 300 K as a function of the X-ray dosetime (tdose). The XAS pre-edge structure at hv = 532.6 eV
was not observable for the uncured TGDDM and DDS,
and was found to originate from the curing process of
TGDDM-DDS, that is, formation of the OH group andthe possible oxidation, as confirmed by the fluorescenceyield XAS. The TEY-XAS spectra show the evidence forthe radiation damage; the pre-edge structure at hv = 532.6
eV gets weakened with tdose. The XAS intensity plot at hv= 532.6 eV as a function of tdose exhibits the exponential
decay, as shown in the inset of Fig. 1. Here, the XAS
intensity (IXAS) plot can be fitted by
IXAS = Iinf + C exp(−tdose/tcdose)

photon flux and the absorbed energy by one photon,
K = Nph tdose × hv (1 − T)/(λ S ρ)

(2),where T, λ, and ρ are the transmission probability, theprobing depth, and the material density (1.05 g/cm3 for
TGDDM-DDS), respectively. If the photoelectron
attenuation length in materials (typically, nm order) is
short enough with respect to the photon irradiation area,
the charged-particle equilibrium would exist, and the
kerma is equal to the absorbed dose (Da), Da/K = 1.
When λ is 2~10 nm for O K-edge TEY-XAS ofpolymers, the transmission probability is calculated to
be T = 0.99265 (λ = 6 nm) by using Ref. [2]. These
parameters give the critical absorbed dose (Dca) of
3.83±0.01 MGy. The small error in Dca of ±0.01 (lessthan 0.3 % for Dca) indicates that the critical absorbed
dose does not depend on the probing depth so much, if
the probing depth is sufficiently shallower than thepenetration depth of photons.
By using the X-ray emission spectroscopy with thehighly-brilliant and well-focused soft X-ray beam at
SPring-8 BL17SU (Nph = 3×1011 ph/s, S = 0.001 mm2),
we found that the half of Dca is applicable for the nondestructive chemical-state analysis of adhesivematerials [3]. These results indicate that the chargedparticle equilibrium exists for soft X-rays in the rangeof at least 0.001~0.847 mm2 beam spot.

(1),

where Iinf, C, and tcdose are the XAS intensity at thesaturated damage region, a constant, and the criticaldose time for the chemical change, respectively [1]. The
least-squares fitting using Eq. (1) with IXAS = 1.0 at tdose= 0 s gives Iinf = 0.853, C = 0.147, and tcdose = 4968 s.
The critical flux density (Nph tcdose / S) is thus determined
as 3.68×1013 ph/mm2.
The kinetic energy released in materials (kerma, K) is
expressed as the product between the accumulated

Fig. 1. O K-edge TEY-XAS spectra measured for
TGDDM-DDS as a function of the X-ray dose.
[1] X. Zhang et al., J. Vac. Sci. Tech. B 13 (1995) 1477.
[2] http://henke.lbl.gov/optical_constants/[3] H. Yamane et al., J. Electron Spectrosc. Relat.
Phenom. 232 (2019) 11.

125
Ⅲ03- 15 -Ⅲ-3

Ⅲ -3. Chemistry
BL6B
BL6B

Redistribution of Molecular Orbital Levels in Platinum-dithiolene Complex
T. Yamamoto1,2,3, D. Hiraga4, I. Arashi1, T. Naito1,2, T. Teshima5, K. Tanaka5 and R. Kato3
Graduate School of Science and Technology, Ehime University, Matsuyama, 790-8577, Japan.
Geodynamics Research Center, Advanced Research Unit for High-Pressure, and Research Unit forSuperconductivity, Ehime University, Matsuyama, 790-8577, Japan
3
RIKEN, Wako, 351-0198, Japan
4
Department of Science, Ehime University, Matsuyama, 790-8577, Japan
5
UVSOR Synchrotron Facility, Institute for Molecular Science, Okazaki 444-8585, Japan
1

2

Ⅲ-3

Orbital degrees of freedom in inorganic and multifunctional solids have been attracted attention. In the fieldof molecular solids, on the other hand, only a few efforts
have been devoted to studying the physical properties
originating from the orbital degrees of freedom. We havefocused on the molecular orbital (MO) of X[Pt(dmit)2]2(dmit = 1,3-dithiole-2-thione-4,5-dithiolate and X =monovalent cation). The suppression of the charge
disproportionation by the irradiation of near-infrared
lights as well as the electric transitions in the infrared andnear-infrared regions suggests the proximity of MOlevels near Fermi energy [1].
Accumulation of our recent study concerning
X[Pd(dmit)2]2 revealed that the C=C stretching modes areuseful to studying how electrons occupy orbitals. We
have examined the proximity and/or degeneration in the
MO levels of X[Pt(dmit)2]2 based on the behavior of the
C=C stretching modes. The Raman and IR spectra wereobserved in Instrumental Center and UVSOR,
respectively. Firstly, the polarization dependence of thereflectance spectra in a single crystal was observed byusing of the infrared microscope. Secondary, weobserved the transmission spectra by using of the KBrpellet method. We confirmed that there is no remarkabledifference between the C=C stretching modes in thereflectance spectra and those in the transmission spectra.
In the last step, we observed the temperature dependenceof the transmission spectra.
Figure 1 shows the transmission spectra of X =Me4Sb (left) and Me4P (right). The phase transition
temperature of X = Me4Sb (180 K) turned out to belower than that of X = Me4P (200-220 K). Factor group
analysis in the low-temperature phase reveals that the
charge-rich dimer ([Pt(dmit)2]2-1-Δ) and the charge-poor
dimer ([Pt(dmit)2]2-1+Δ) are alternately arranged in thetwo-dimensional layer, which indicates no remarkablevalence bond ordering in the inter-dimer interaction. This
result is in contrast to the charge distributions ofX[Pd(dmit)2]2, where the anti-bonding orbitals of two
charge-rich dimers form valence bond. The absence of
the inter-dimer valence bond in the low-temperaturephase of X[Pt(dmit)2]2 indicates that the redistribution in
the MO levels occurs at the phase transition temperature.
Furthermore, the mutual exclusion rule cannot be applied
to both IR and Raman spectra, which reveal that dimers
becomeasymmetricoriginatingfromthedisproportionation between two ligands in a monomer.
This result is striking because the disproportionation ofmonomers might explain the conducting properties of thesingle component metals and superconductors.
[1] T. Ishikawa et al., Science. 350 (2015) 1501.
[2] T. Yamamoto et al., Sci. Rep. 7 (2017) 12930.

Fig. 1. Transmission spectra of X = Me4Sb (left) and Me4P (right).

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