Annual Review
2021

Molecular Photoscience
Research Center

Kobe University
12Preface
This annual review summarizes the research activity of Molecular Photoscience Research Center
conducted in the 2021 academic year. We are further promoting advanced research and international
collaboration on molecular photoscience and related topics. Any constructive comments and questions,and any suggestion for collaboration research are welcome.
Since 2017 we have been running joint usage/research project on molecular science in the terahertz
frequency region, which is open to domestic universities and research institutes. In this year 33 joint
research projects were accepted, and the research area spans from solid state physics, biophysics, solution
chemistry, polymer science, photochemistry, theoretical physics and chemistry, so on. Although there weremany difficulties and restrictions to conduct joint research due to the COVID-19, we have made goodachievements in many research themes. The research center will continue to make efforts to push forward
international and domestic collaborative research.
April, 2022
Keisuke Tominaga
Director of Molecular Photoscience Research Center,
Kobe University

3

Contents
Members

5

Research Activities
Laser Molecular Photoscience Laboratory

7

Terahertz Molecular Chemistry Laboratory

17

Terahertz Material Physics Laboratory

28

Original Papers

44

Invited Talks

49

Presentation at Conferences (International and domestic)

51

Presentation by Graduate Students and Postdocs

54

Books

58

Other Publications

59

Lectures to Public

60

Awards61

Conference Organization

62

Seminars

63

4

Members
Keisuke Tominaga

Director

Hitoshi Ohta

Vice-Director

Takako Miyazaki

Assistant

Kei Kita

Assistant

Ryoko Ikeuchi

AssistantLaser Molecular Photoscience Laboratory
Yasuhiro Kobori

Professor

Shunji Kasahara

Associate Professor

Takashi Tachikawa

Associate Professor

Masaaki Fuki

Research AssistantTsubasa Okamoto

Project Research Assistant (September 2021 ~ )Yoshitaka Kumabe

Academic Researcher (April 2021 ~ )Appu Vengattoor Raghu

Academic Researcher (April 2021 ~ November 2021)

Masaaki Baba

Visiting Professor

Terahertz Molecular Chemistry Laboratory
Keisuke Tominaga

Professor

Kaoru Ohta

Research Colaborator (April ~ September 2021),
Academic Researcher (October 2021~)

Feng Zhang

Research Assistant (~ August 2021),
Research Colaborator (December 2021 ~)Harumi Sato

Professor (Supplementary assignment. Main assignment is Graduate Schoolof Human Development and Environment)

Yukihiro Ozaki

Visiting Professor

Terahertz Material Physics Laboratory
Hitoshi Ohta

Professor

Susumu Okubo

Associate Professor

Hideyuki Takahashi

Assistant Professor

Mitsuru Akaki

Research Associate (~ March 2022)

Makoto Saga

Part-time Research Associate (April 2021 ~ March 2022)

Kohta Mitsumoto

Academic Researcher (April 2021 ~ March 2022)

Toshiro Kohmoto

Professor (Supplementary assignment. Main assignment is Graduate Schoolof Science)5

Eiji Ohmichi

Associate Professor (Supplementary assignment. Main assignment is
Graduate School of Science)

Hikaru Kawamura

Visiting Professor

6Research Activity
I. Laser Molecular Photoscience Laboratory
I-A.

SPIN INTERACTIONS STUDIED BY TIME RESOLVED MAGNETIC RESONANCE
SPECTROSCOPY

In the natural photosynthesis, the organic solar cells and the photocatalysis, transient radical species or carriers
are immediately generated by the light-induced chemical reactions for the photo-energy conversion, providing
essential sources of the living energies. However, it has been unclear how those transient molecules are initiallyinteracting each other before the carrier-conductions or charge-dissociation take place. In our group, we aredeveloping experimental methodologies to determine molecular positions, orbital orientations and orbital
overlap (electronic coupling) in the initially generated radical-pairs, multiexcitons, and electron-hole pairs in
the photoactive proteins, in the solar cells, and in the photocatalysis on the basis of the transient electron
paramagnetic resonance (EPR) method. We have clarified several fundamental mechanisms of the energyconversions in semiconductor nanoparticles, singlet-fission materials and in the polymer systems.

by(i.e., vibration, rotation, and fluctuation) and their

Molecular Design: Perspective from “Dynamic

collective motions controlling behaviors of electrons

Exciton”

and spins by the passage of time. The concept of

H. Imahori1, Y. Kobori, H. Kaji1“dynamic exciton” should cover a wide variety of the1

Kyoto University

photochemical phenomena that are all essential for the(Acc. Mater. Res., 2021)

energy conversion devices and processes including“Dynamic exciton”, an umbrella term concept invarious kinds of living systems. In these, a huge

photochemistry, plays an important role in nature,amount of the nuclear motional modes may

science, and technology, especially in photoinduced

cooperatively be entangled to electronic orbitals. Thus,and electrically induced electron transfer (ET)the idea behind “dynamic exciton” includes usage of

between a donor (D) and an acceptor (A). Typically,

the cooperation between nuclear motions and the spin–

ManipulationofCharge-Transfer

Statesan exciton in molecular D–A systems is considered a orbital, as electron–phonon coupling for innovative
locally excited (LE) state of a donor (D*) or andesigns of the energy conversion materials andacceptor (A*) molecule, but let us extend theassemblies. For this, it is particularly important toterminology of “exciton” to an integrated class of LE,

examine how this wide variety of the motions plays

charge-transfer (CT), and charge-separated (CS) states. roles on electronic couplings, intermediate geometries
The degree of CT (0–100%), spin multiplicity, and D–

and mobilities, exciton energies, CT characters, and so

A interaction (i.e., electronic coupling) are pivotal

on. We draw researchers’ attention to this aspect of thefactors in the “exciton”. Another important aspect ofvibronic effect, like the entropy role by collective

the “exciton” is strongly related to the “dynamic”

movement of side chains of the conjugated polymer toaspect of the “exciton” by movement of atomic nuclei modulate the electronic coupling time-dependently at7

the charge delocalization and dissociation, which is

OPVs is an opposite process to that of the CS state-to-reinforced three-dimensionally at the D/A domain

excited state in organic light-emitting diodes (OLEDs).

interface of organic photovoltaics (OPVs). In addition,

Specifically, intramolecular D–A linked systems andto realize the ultimate high-performance OPVs, theintermolecular D–A systems hold a prominent position

voltage loss must be diminished; i.e., the energy

in both OPVs and OLEDs, and an intrinsic similarity

difference between the band gap and the open circuit is seen in the mutual interplay among LE, CT, and CS
voltage is caused in part by interfacial charge

states of such systems facilitated by the dynamic

recombination via vibrational relaxation. Attaining effects. These facts encourage us to work on theefficient excited-state migration with prevention of the manipulation of CT states by logical molecular design,
vibrational relaxation at the D/A interface would

achieving efficient energy conversion in OPVs andpossibly overcome the voltage loss issues at the

OLEDs. Along with some examples of OPVs andprimary CT event, when we understand the roles of OLEDs, here we introduce the “dynamic exciton” as a
low-frequency disorder movements by the phonon oncomprehensive, CT photochemistry in molecular D–A

the vibrational relaxation in the solid state. Importantly, systems, eventually making innovations in electronics,
conversion of the excited state-to-CS state in organic

Enthalpy–Entropy

Compensation

Effectenergy, medicine/health care, and functional materials.

for first observation of the quantitative TT generation

Triplet Pair Dissociation of Intramolecular Singlet

together with the orientation-dependent photophysicalFission in Phenylene Spacer-Bridged Hexacene

discussions for TT dissociation using para- and meta-

Dimersphenyl-bridged Hc dimers. Moreover, the activation

S. Nakamura1, H. Sakai1, M. Fuki, Y. Kobori, N. V.

enthalpies of Hc dimers in TT dissociation are smaller

Tkachenko2, T. Hasobe1than those of pentacene (Pc) dimers, whereas the1

Keio University

relative entropic contributions for Gibbs free energy of2

Tampere University

activation are much larger than the enthalpic ones in(J. Phys. Chem. Lett., 2021)

both Hc and Pc dimers. This implies that the

Hexacene (Hc) is highly promising for singlet fission

vibrational(SF). However, the number of SFs in Hc is extremely

intramolecular conformation changes associated withlimited. As far as Hc dimers in solution are concerned,

the TT dissociation. Consequently, “enthalpy–entropy

there is no report on the observation of the dissociationcompensation” has a large impact on the rate constants

process from a correlated triplet pair (TT) to an

and quantum yields.

motionsareresponsible

for

the

individual one. The emphasis in this study is on the

Synergetic Role of Conformational Flexibility and

S. Nakamura1, H. Sakai1, H. Nagashima, M. Fuki,

Electronic

K. Onishi, R. Khan2, Y. Kobori, N. V. Tkachenko2,

Coupling

forIntramolecular Singlet Fission

Quantitative

T. Hasobe18

1

Keio University

coupling

2

Tampere University

exhibited the quantitative ΦΤ: 196 ± 12% at high

(J. Phys. Chem. C., 2021)

excitation

We present a novel design concept of molecularassociated with conformational change were directly

dimers for quantitative individual triplet yield (ΦΤ)

characterized by time-resolved electron paramagnetic

through intramolecular singlet fission. We synthesizedresonance. Strong interplay of the geometry change

a series of tetracene (Tc) dimers bridged by different

and electronic localization was revealed on the triplet

phenylene-based

thepair dissociation through magnitudes of spin–spin

conformational flexibility in addition to the electronic

exchange couplings. Thus, a synergetic role ofcoupling. In transient absorption measurements, aconformational flexibility and electronic coupling in

4,4′-biphenyl-bridged Tc dimer with weaker electronic

quantitative ΦΤ was clarified.

Orientations and water dynamics of photoinduced

prior to the terminal RP states. In this study, watersecondarylinkers,

focusing

charge-separated

onstatesandlargerenergy.

conformational

Moreover,flexibility

decoupledspins

for dynamics control of the electronic coupling is revealed

magnetoreception by cryptochrome

to be a key concept for sensing the direction of weak

M. Hamada, T. Iwata1, M. Fuki, H. Kandori2, S.

magnetic field. Geometry and exchange couplingWeber3, Y. Kobori(singlet–triplet energy gap: 2J) of photoinduced

1

Toho University

secondary CS states composed of flavin adenine

2

Nagoya Institute of Technology

dinucleotide radical anion (FAD−•) and radical cation

3

Albert-Ludwigs-Universität Freiburg

WB(H)+• in the cryptochrome DASH from Xenopus(Commun. Chem., 2021)

laevis were clarified by time-resolved electron

In the biological magnetic compass, blue-lightparamagnetic resonance. We found a time-dependent

photoreceptor protein of cryptochrome is thought toenergetic disorder in 2J and was interpreted by a trap

conduct the sensing of the Earth’s magnetic field by

CS state capturing one reorientated water molecule at

photoinduced sequential long-range charge-separation

120 K. Enhanced electron-tunneling by water-(CS) through a cascade of tryptophan residues, WA(H), libration was revealed for the terminal chargeWB(H) and WC(H). Mechanism of generating theseparation event at elevated temperature. This

weak-field sensitive radical pair (RP) is poorly

highlights importance of optimizing the electronic

understood because geometries, electronic couplings

coupling for regulation of the anisotropic RP yield on

and their modulations by molecular motion have not

the possible magnetic compass senses.

been investigated in the secondary CS states generated

Molecular Design Strategy for High-Yield and

T. Hasobe1, S. Nakamura1, N. V. Tkachenko2, Y.

Long-Lived Individual Doubled Triplet Excitons

Koborithrough Intramolecular Singlet Fission

1

Keio University9

2

Tampere University

achieving efficient photoenergy conversion. In this(ACS Energy Lett., 2022)

Focus Review, we discuss the molecular design

Multi-exciton generation of organic chromophores,

strategy for high-yield and long-lived individual triplet

i.e., singlet fission (SF), is highly promising for

exciton generation through intramolecular SF utilizing

photoenergy conversion such as photocatalysis anda series of acene derivatives such as hexacene,

photovoltaics. Among the reported high-yield SF

pentacene, and tetracene. In addition to clarifying thesystems, many systems possess only short-lived triplet

structural and vibronic characters required for high-excited states derived from correlated triplet pairyield individual triplet exciton generation, specificintermediates, but not individual doubled triplet

examples of the photoenergy conversion far exceeding

excitons.

long-lived

100% quantum yields of subsequent electron-transfer

individual triplet exciton generation is favorable for

products and singlet oxygen generation are presented.

Identification of Self-Photosensitizing Hydrogeninteractions to form electron donor−acceptor (EDA)

Atom Transfer Organocatalyst Systemcomplexes. Photoirradiation of the EDA complex

H. Fuse1, Y. Irie1, M. Fuki, Y. Kobori, K. Kato2, A.

induced stepwise, sequential single-electron transfer

Yamakata2, M. Higashi3, H. Mitsunuma1, M.

(SET) processes to generate a HAT-active thiyl radical.

Kanai1

The first SET was from the electron-rich naphthyl

1

The University of Tokyo

group of 7,7’-OMe-TPA to the protonated N-

2

Toyota Technological Instituteheteroaromatics and the second proton-coupled SET

3

Kyoto University(PCET) from the thiophosphoric acid moiety of 7,7’-(J. Am. Chem. Soc., 2022)

OMe-TPA to the resulting naphthyl radical cation.

We developed organocatalyst systems to promote theSpectroscopic studies and theoretical calculations

cleavage of stable C−H bonds, such as formyl, α-characterized the stepwise SET process mediated byhydroxy, and benzylic C−H bonds, through ashort-lived intermediates. This organocatalytic HAThydrogen atom transfer (HAT) process without the use

system was applied to four different carbon−hydrogenof exogenous photo- sensitizers. An electronically(C−H) functionalization reactions, hydroxyalkylation

tuned thiophosphoric acid, 7,7’-OMe-TPA, wasand alkylation of N-heteroaromatics, acceptorlessassembled

dehydrogenation of alcohols, and benzylation of

However,withhigh-yield

substrateorandco-catalyst

N-heteroaromatics through hydrogen bonding and π−πI-B.

imines, with high functional group tolerance.

SINGLE-MOLECULE STUDIES ON PHOTO-ENERGY CONVERSION PROCESSES

To design a more efficient solar energy conversion system (light energy to electrical or chemical energy), it isimportant to reveal and understand the mechanisms of various chemical reactions at heterogeneous interfaces.
We have investigated the photochemical and photophysical processes occurring on a variety of lightenergy conversion systems such as photocatalysis and solar cells using advanced single-molecule, single10

particle spectroscopy techniques and gain new insights related to spatial and temporal heterogeneities inreactions and structures, which are always masked by ensemble averaging. We also developed in situ analysis
techniques for visualizing and linking macro- and nanoscopic features of external stimulus-responsive
luminescent materials.

Dynamic Symmetry Conversion in Mixed-Halide

which is a characteristic signature of a single particle.

Hybrid Perovskite upon Illumination

The independent blinking of the red PL signals

Satoshi Tominaka,1 Izuru Karimata, Takahide

suggests the formation and dissociation of emissive

Matsuoka,2 Moeri Sakamoto, Takahito Nakajima,2sites for lower-energy PL. The probability distribution

Koji Ohara,3 Takashi Tachikawaof the red PL duration time followed a single-

1

National Institute for Materials Scienceexponential curve with a characteristic lifetime of 6.8

2

RIKEN

s, which is close to the reciprocal of the backward rate

3

Japan Synchrotron Radiation Research Instituteof change. Therefore, the increasing PL under intense(ACS Energy Lett., 2021)

excitation conditions is ascribed to the accumulation

Organic–inorganic hybrid halide perovskites haveof emissive local domains with a specific lifetime.

excellent optoelectronic properties and are highly

Combined with the results of synchrotron-based X-ray

efficient photovoltaic materials, but their chemical

analysis, we suggest a defect-assisted photoinduced

instability impedes their development for use in next-transition from ordinary nonpolar phases to polar

generation solar cells, wherein they serve as the lightphases at the local scale within seconds is coupled withharvesting material. Here, we report a mechanism oforganic cation reorientation, which in turn narrows thephotoluminescence red-shift, a performance-loss

bandgap (Figure 1). First-principles calculations

phenomenon

known

halidequantitatively supported this result. Our findings

segregation,

inperovskites

provide deeper insights into the nature of local polar(CH3NH3PbBr1.5I1.5) upon illumination using in situ

domains in hybrid perovskite materials and help

single-particle spectroscopy and synchrotron-based X-

improve device stability and efficiency.

aslight-induced

mixed-halide

ray techniques. Under 405 nm excitation, thephotoluminescence (PL) intensity gradually increased
over time, and the peak position shifted from 640 to
720 nm. To explore the mechanism of PL red-shift, wemeasured the PL emission from individual spots overtime in two wavelength regions: 574–626 nm,
originating from the as-prepared particles; and 672–
696 nm, which slowly increases with a weak excitation
intensity. The red PL signals from individual
nanoparticles

exhibitedablinking

behavior(intermittent on and off PL) during the initial stage,

Figure 1. Photoinduced change of local structure andemission color on CH3NH3PbBr1.5I1.5 under 405 nm
laser irradiation.
11

In Situ Exploration of Stimulus-Induced Emission

structures, breaking the intermolecular interactions

Changes in Mechanochromic Dyes

between stacked molecules at a certain depth, thus

Maho Yamashita, Sayaka Nagai,1 Suguru Ito,1leading to more planar conformations with increased

Takashi Tachikawa

rotational degrees of freedom. Such structural changes

1

Yokohama National University

are more effectively produced by scrubbing or(J. Phys. Chem. Lett., 2021)

grinding the particles, rather than by simple cutting.

The development of in situ analysis techniques for Moreover, the correlative fluorescence and atomic
visualizing and linking macro- and nanoscopic

force

features of external stimulus-responsive materials isquantitative information about mechanically induced

crucial for their rational design and applications.

dissociation of stacked molecules in the crystal. Our

Herein, we investigate the mechanical stress induced

method has the potential to become a generalemission changes in electron donor–acceptor type

technique for in situ analysis of MCL processes,organic dye molecules in solid states through in situ

including structural fluctuation between different

microscopy(AFM)

imagingprovided

single-particle fluorescence spectroscopy combined states, and other stimulus-responsive materials such aswith macroscopic and nanoscopic stimulation systems. triboluminescent materials.
Mechanochromic luminescence (MCL) behavior is
the reversible color change in the emission from solidstate dyes upon mechanical stimuli such as grinding
andstretching.

Phenanthroimidazolylbenzo-

thiadiazole (PB) dyes have exhibited versatile MCL
properties, e.g., the change in emission color fromgreen to yellow by gentle grinding. The piezocontrolled mortar and pestle system developed herein
reproduces the usual grinding operation and fills the

Figure 1. Illustration of the fluorescence microscope

gap between the macro and nanoscales. The observedwith AFM system (left). Emission images andmechano-induced transition from the green-emissive

spectrum acquired for a PB crystal before and after the

crystalline state to the yellow-emissive state was stimulation with the AFM tip (right).
attributed to the partial disordering of (near) surface

Organic photostimulated luminescence associated2with persistent spin-correlated radical pairs(Commun. Mater., 2021)

Manabu Sakurai, Ryota Kabe,1 Masaaki Fuki,

Photostimulated luminescence (PSL) allows energy or

Zesen Lin,1 Kazuya Jinnai,2 Yasuhiro Kobori,data to be stored and released using electromagnetic

Chihaya Adachi,2 Takashi Tachikawa

waves as both the input and output, and has attracted

1

Okinawa Institute of Science and Technology

considerable interest in the fields of biomedical and

Graduate University

information technologies. However, this phenomenon

Kyushu University12

is mostly limited to solid inorganic materials. In thiselectromagnet to the sample under the inverted

paper, we demonstrate purely organic PSL over a wide

fluorescence microscope. Interestingly, significant

range of colors utilizing ultraviolet (UV) and near-decreases of emission intensity (i.e., negative MFEs)

infrared (NIR) light for multiple write-in and read-out

were observed for LPL/PSL, while no MFE was seen

cycles, respectively, by adding a molecule with dual

for the film without Rb, implying a crucial role ofroles as an electron trap and light emitter to the organic

trap/emitter molecules. Combined with write-in andlong persistent luminescence (LPL) systems. As aread-out characteristics of PSL, manipulation of long-model system, we show a ternary blend film of

lived spin states in organic materials by weakelectron donor (m-MTDATA) (1mol%), electron

magnetic fields will energize researchers in various

acceptor (PPT), and electron trap/emitter (Rb)fields such as molecular spintronics, which is a

(1mol%). Excitation of the film with UV light induces

promising next generation technology.

the formation of charge-separated states (CSSs)
between m-MTDATA and PPT, resulting in a green
2000

emitting charge transfer (CT) excited state or exciplex.

(Rb•−). Since Rb•− possesses strong absorption bands
in the NIR region, NIR excitation can induce electron

Intensity (a.u.)molecules to form the long-lived radical anions of Rb

transfer from doublet excited Rb•− to neighboring PPT1500

NIR onχLPL(B) (%)

0

A portion of the electrons are captured by neutral Rb

-2

-4

1000

0

20
40
Magnetic field (mT)500

NIR off

molecules, thereby producing mobile electrons in the0

PPT film for the generation of singlet excited state of

0 10

100

120

140

160

180

200

Time (s)1

Rb ( Rb*). Furthermore, the spin state of trappedcharges could be controlled by magnetic fields. We

Figure 1. Emission decay profiles obtained for the m-investigated magnetic field effects (MFEs) on

MTDATA/PPT/Rb film with and without 800-nm light

LPL/PSL by applying external magnetic fields with anirradiation. The inset shows the MFEs on LPL.

I-C.

HIGH-RESOLUTION SPECTOSCOPY OF POLIATOMIC MOLECULES

Doppler-free high-resolution spectroscopy is a powerful tool for studying the structure and dynamics of excitedpolyatomic molecules in detail and unambiguously. Single-mode auto-scan laser systems for the UV-VisibleNIR region, absolute wavenumber measurement systems, and Doppler-free high-resolution spectroscopic
measurement systems have been constructed to investigate the excited molecules. High-resolution and highprecision measurement of spectral lines enables to observe rotationally-resolved electronic transition, then it isexpected to find the excited state dynamics such as internal conversion (IC), intersystem crossing (ISC), andintramolecular vibrational redistribution (IVR) through the deviations in spectral line positions, intensity
anomalies, and the changes of spectral linewidth. We have observed the high-resolution spectrum and the
Zeeman effect of the π-π* transition of several aromatic molecules such as benzene, naphthalene, anthracene,13etc. and these molecular constants were determined in high-accuracy. Recently, we extended our observation
to the molecules with large amplitude motion such as acetaldehyde and trans-stilbene.

Ultrahigh-resolution

Laser

Spectroscopyofacetaldehyde:

Torsion-inversion-rotation

Nakajima,

1) L.-H. Xu, J. T. Hougen et al., J. Mol. Spectrosc. 214,
175 (2002).

interaction in the excited state
KosukeReferences:

Akira

Shimizu,

Shunji2) I. Kleiner, J. T. Hougen, J.-W. Grabow et al., J. Mol.

Kasahara, Masatoshi Misono1, Masaaki Baba

Spectrosc. 179, 41 (1996).

(2021

3) M. Baba, I. Hanazaki, and U. Nagashima, J. Chem.

International

Symposiumon

Molecular

Spectroscopy)

Phys. 82, 3938 (1985).

1

Fukuoka University4) M. Baba, U. Nagashima, and I. Hanazaki, J. Chem.

Li-Hong Xu, Jon Hougen, Isabelle Kleiner, Jens-Uwe

Phys. 83, 3514 (1985).

Grabow et al. beautifully analyzed ro-vibrational

5) E. C. Lim, R. H. Judge, D. C. Moule et al., J. Mol.

levels in the ground state of acetaldehyde taking CH3-

Spectrosc. 190, 78 (1998).

1,2)

torsion rotation interaction into consideration. For6) I.-C. Chen et al., J. Chem. Phys. 115, 5089 (2001).

the lowest electronic excited state S1 (nπ*) state, thero-vibrational

level

structure

is

much

more

complicated because of the out-of-plane distortion in
the CHO moiety (tunnel splitting due to double
minimum potential) in addition to the profound levelstructure of CH3 torsion3,4). We observed and analyzed
rotationally resolved ultrahigh-resolution spectra for
the S1←S0 transition of jet-cooled acetaldehyde, of
which the resolution was much higher than thosereported previously5,6). The effective rotational
constant Aeff was found to be drastically different
between the levels of below and above the barrier toFigure 1. Observed rotationally-resolved high -CH3 rotation. We well explained this fact byresolution spectra of acetaldehyde S1←S0 transition

considering the mechanism of Coriolis interaction andaround 30375 and 30118 cm-1.

estimating the interaction strength by a model
calculation.

Ultrahigh-resolution

spectroscopyoftrans-

stilbene: nonplanar structure in the ground state
Akira

Shimizu,

KosukeNakajima,

ShunjiKasahara,

Nakayama1,

NaofumiMasatoshi,

Misono2, Masaaki Baba
(2021
14

International

Symposiumon

Molecular

Spectroscopy)

ethylene part surpasses stabilization by π conjugation.

1

Conflex Corporation

References:2

Fukuoka University

1) J. A. Syage, P. M. Felker, and A. H. Zewail, J. Chem.

Trans-stilbene is of great interest in the excited-statePhys. 81, 4706 (1984).

dynamics such as cis-trans isomerization in the2) B. B. Champagne, J. F. Pfanstiel, D. F. Plusquellic,electronic excited state. Zewail et al. reported theD. W. Pratt, W. M. van Herpen, and W. L. Meerts, J.

results of time-resolved spectroscopy and suggested

Phys. Chem. 94, 6 (1990).

1)

its nonplanar structure in the ground S0 state . In
contrast, Pratt et al. concluded that the molecule isessentially planar both in the S0 and S1 states byanalyzing the rotationally resolved high-resolution
spectrum of the S1←S0 0-0 band 2). We observed thespectrum with much higher accuracy and quality, andre-determined the rotational constants. Although it is
impossible to accurate determine the absolute value of
A for the a-type transition, we could conclude thattrans-stilbene is nonplanar in the S0 state. Theoretical
calculation using WB97XD functional provided thenonplanar structure in which the phenyl rings arerotated around the C-C bond axis and take the C2

Figure 1. A part of the observed spectra of the 0-0
band of trans-stilbene S1←S0 transition for P branchregion.

symmetry. It suggests that steric repulsion between H
atoms of ortho-position in a phenyl ring and in an

I-D.

HIGH-RESOLUTION SPECTROSCOPY OF NO2 AND NO3 RADICAL

Nitrogen dioxide NO2 and nitrate radical NO3 have been known as an important intermediate in chemical
reaction in the atmosphere. These radicals are the prototype molecules to understand vibronic interaction as
followings; the Renner-Teller effect for NO2, and the Jahn-Teller (JT) and pseudo Jahn-Teller (PJT) effects forNO3. Optically allowed transitions have been observed as strong absorption and LIF excitation spectra by
several research groups. For NO2 radical, hyperfine splitting were observed in the high-resolution spectrum,and the magnitude of the hyperfine interaction constants suggest the state mixing between the electronic excitedstate and the ground state through the vibronic interaction. Recently, we reported the hyperfine-resolved highresolution spectrum NO2 A-X system for the 14500-16800 cm-1 region, and found the anomalies of thehyperfine splitting around 16200 cm-1, which suggested to the interaction with other electronic state(s) in thisenergy region.

15

High-resolution Laser spectroscopy of 14NO2 andIn this work, we have observed the rotational structure

15NO radicals
2

for 15885 and 16218 cm-1 bands to find the

Shunji Kasahara, Kazuho Norii, Ikki Hosomi,

perturbations. Furthermore, the hyperfine structure of

Honoka Minamide, and Kohei Tada

15

NO2 16324 cm-1 band was also observed.

(Annual Meeting of Japan Society for Molecular
Science 2021)
Hyperfine-resolved

q

R0(4)

q

high-resolution
2

R0(2)

fluorescence

q

P0(8)

q

P0(6)

q

P0(4)

q

q

P0(2)

q

R0(0)

R0(6)

2

excitation spectra of the A B2 ←X A1 electronictransition of 14NO2 and 15NO2 radical have been
observed by crossing a single-mode laser beam

16210.016215.016220.0q

perpendicular to a collimated molecular beam.

qqRecently, we reported the hyperfine structure of theq

16800 cm energy region of

14

(×14)

NO2. The determined

Fermi contact interaction constants shows a sharp-1

decreasing in 16200-16600 cm region, and it may be-1

R0(0) F1

R0(0) F1

R0(0) lines (k = 0, N = 1←0 transition) in 14500-1

R0(0) F1

Wavenumber/cm

16216.41

16216.42(×7)
16216.80

16216.82(×2)
16218.00
16218.02
Wavenumber/cm -1

Figure 1. Observed high-resolution spectrum of
16218 cm-1 band. Upper trace: rotational structure.

caused by the interaction with the other electronic state. Lower trace: hyperfine splitting for qR0(0) lines.

16II. Terahertz Molecular Chemistry Laboratory
II-A.

LIQUID DYNAMICS STUDIED BY NONLINEAR INFRARED SPECTROSCOPY

Molecular dynamics in liquids are strongly affected by the nature of intermolecular interactions. It is greatly
important to obtain the molecular description on relation between the dynamics and interactions in liquids inorder to elucidate the solvent dynamical effect on chemical reactions. In solutions, a vibrational frequency ofsolute molecule is sensitive to changes of the solvent environment. Especially, in aqueous solution, hydrogenbond making and breaking processes play an important role in the dynamics of water molecules surrounding
the solute. Fluctuations of the vibrational transition energies, which are characterized by time correlation
functions of the frequency fluctuations, are very sensitive to the dynamics of surrounding environments.
Vibrational energy relaxation is also affected by short-range solvent-oscillator interaction.
Furthermore, orientational relaxation reflects microscopic viscosity around the oscillator. In recent years,
a great deal of effort has been devoted to investigate solute-solvent interactions with infrared (IR) nonlinear
spectroscopy such as two-dimensional IR (2D-IR) spectroscopy and pump-probe spectroscopy. 2D-IR
spectroscopy is a powerful tool to obtain microscopic information in solution such as ultrafast solvent dynamics
and local structure of solvent by probing the vibrational frequency fluctuations. By polarization-sensitive pumpprobe spectroscopy in the IR region we can study vibrational energy relaxation and orientational relaxation.

Temperature

DependenceofVibrationalof the CO stretching modes of solute molecules with

Frequency Fluctuation of Solutes in Water Studied aromatic rings of different sizes in D2O by using twoby Two-Dimensional Infrared Spectroscopy

dimensional (2D) IR spectroscopy. Furthermore,

Yuki Fujii, Masaki Okuda, Kaoru Ohta, Keisuke molecular dynamics (MD) simulation was performed
Tominagath(11 Asian Photochemistry Conference, 2021)

to obtain a molecular picture of the frequency
fluctuation.

The vibrational frequency is sensitive to sub-ps time

In 2D-IR spectroscopy, three mid-infrared

evolving structural fluctuation of solvent molecules pulses were used to obtain correlation of theand hence the frequency fluctuations provide vibrational transition dipoles between at pump and at
microscopic information such as local hydration probe pulses irradiated. It is known that the shape ofstructure or solute-solvent interaction. Our group has 2D-IR spectrum changes from ellipse to circle ininvestigated the vibrational frequency fluctuations of population time reflecting the frequency fluctuation.
various ionic solutes in aqueous solutions by nonlinear Therefore, we applied center line slope (CLS) analysis
infrared spectroscopy at room temperature. On the to 2D-IR spectra to obtain decay time of correlation
other hand, temperature dependence of the frequency function of the frequency fluctuation. The CLS curves
fluctuation has not been studied in detail so much. were fitted with a single exponential function. We
Moreover, there are few detailed reports for solutes found that the decay time becomes longer with
with hydrophobic groups. In this work, we studied increasing the size of aromatic ring. The decay time istemperature dependence of the frequency fluctuation originated from the structural fluctuation of hydrogen-17

bond network structure nearby the solute. As for the frequency fluctuation and its activation energy.
temperature-dependent 2D-IR measurements, we MD simulation results showed that the hydrationconsidered Arrhenius equation for the decay times and structures in the vicinity of the solute molecules are
obtained activation energy of FL (17.2 kJ/mol), ID significantly different from those in bulk region.
(14.3 kJ/mol), OCP (14.8 kJ/mol) and AC (10.2 Therefore, it is suggested that the number of water
kJ/mol). It is found that similar aromatic ring size molecules affected by the aromatic rings is importantdependences were observed in both the decay times of to understand the frequency fluctuations.

Vibrational Frequency Fluctuation of Carbonyl

fluctuation is extracted from center line slope (CLS)

Compounds in Water Studied by Two-Dimensional

analysis. The CLS curves of 9-FL and 4-FB are

Infrared Spectroscopy

characterized by single-exponential decay time of 2.7

Yuki Fujii, Masaki Okuda, Kaoru Ohta andand 0.8 ps, respectively. This difference may be

Keisuke Tominaga

attributed to collective orientation of water molecules(International

ConferenceonTime-Resolved with respect to transition dipole moment of thevibrational probe. For 9-FL, motion of water

Vibrational Spectroscopy, 2021)

A vibrational frequency of solute molecule in an molecules on aromatic ring are highly perturbed,
aqueous solution fluctuates due to time-evolving local which results in elongation of effective solute-solvent
hydration structure around the vibrational probe, interaction length, that is, low dielectric environment
which is called as frequency fluctuation. Two- around the CO group. While, since the water
dimensional

infrared(2D-IR)

spectroscopic

molecules around the CO group of 4-FB are easily

measurements have been performed to investigate the oriented to the solute, the solute-solvent interaction at
frequency fluctuation from the point of view of far away from the solute can be negligible. This
microscopic solute-solvent interaction.

microscopic

view

suggests

that

4-FB

mainlyIn this study, we studied the frequency experiences the fluctuation of low-collective waterfluctuation of carbonyl (CO) stretching mode of 9- molecules in the vicinity of the solute, which yields thefluorenone derivative (9-FL) and 4-formylbenzoate fast decay of correlation of frequency fluctuation.
(4-FB) in D2O. The information on frequency

II-B.

DYNAMICS OF ELECTRONICALLY EXCITED STATE IN CONDENSED PHASES

Understanding of dynamics in the electronically excited state is a key issue to elucidate mechanisms in various
photochemical reactions in condensed phases. It is also important for designing and developing new materials
which have characteristic functions. We employ various kinds of ultrafast technique to monitor photochemicaland photophysical invents in sub-pico- to picoseconds time scales. By femtosecond fluorescence up-conversion
technique, dynamics in the electronically excited state can be observed with a time resolution up to 100 fs.
Vibrational dynamics in the electronically excited can be investigate by UV/VIS-pump IR probe technique.

18

Moreover, low-frequency responses by photoexcitation are investigated by UV/VIS-pump THz probe
experiment. Such responses include change of low-frequency vibrational modes induced by photoexcitationand photo-induced changes of charge carrier dynamics.

Nature of Local Charge Carrier Motions in carrier dynamics. By changing a series of linear alkylPorphyrin-Based
Revealedby

Bulk

Heterojunction

Time-Resolved

OpticalFilms

chains to DPP chromophores in BP compounds, one

Pump- can manipulate the morphology and miscibility in BHJ
structure. In contrast to intuitive expectation based on

Terahertz Probe Spectroscopy
Mitsuharu

the structural difference, we found that carrier mobility

Suzuki1, Hiroko Yamada1, and Keisuke Tominaga

weighted by the yield of the photo-generated charge

1Nara Institute of Science and Technology

carriers is similar to each other. In contrast to the large(Chem. Lett., 2021)

difference in the power conversion efficiency, similar

Kaoru

Ohta,

YuichiHiramatsu,

Local charge carrier dynamics in diketopyrrolopyrrole dynamics are observed between C10-DPP-BP and C4(DPP)-tetrabenzoporphyrin(BP)-based

bulk

DPP-BP BHJ films. We consider that this similarity

heterojunction (BHJ) films are investigated by optical comes from the molecular-scale mobility of the photopump-terahertz probe spectroscopy. Here we focus on generated polarons probed by time-resolved OPTP
the effect of the alkyl chain lengths of DPP on the spectroscopy.

Ultrafast

ChargeTetrabenzoporphyrin

Carrier

Dynamics

Derivatives

Studiedin heterojunction (BHJ) thin films using time-resolved
by THz spectroscopy.
Time-resolved THz spectroscopy, i.e., optical

Time-Resolved Terahertz Spectroscopy
Kaoru Ohta, Hiroko Yamada1, Keisuke Tominaga

pump-THz probe spectroscopy, is known to be a1unique technique to obtain the complex-valued

Nara Institute of Science and Technologyth(11 Asian Photochemistry Conference, 2021)

conductivity of photogenerated charge carriers in

Organic semiconductors made of, for example, various systems. In contrast to time-of-flight methods,
conjugated polymers or small-molecules are important time-resolved THz spectroscopy is a contact-freematerials for efficient solar cells. They have a couple method that is intrinsically sensitive to the local chargeof advantages over inorganic-based ones because cost- carrier dynamics with subpicosecond time resolution.
effective and flexible devices can be produced by Since the scattering frequency of the charge carriers inusing solution processing. Tetrabenzoporphrin (BP) is semiconductors is typically in the THz region, THza well-known p-type organic semiconductor that spectroscopy provides detailed information on bothpossesses excellent photophysical properties such as a carrier density and mobility for the systems. Thoughlarge absorption cross section in the visible region and time-resolved THz spectroscopy has been used tohigh hole mobility. We have been studying the charge study the charge carrier dynamics of small-moleculecarrier dynamics of BP derivatives and BP-based bulk based

19

organic

semiconductors,

porphyrin-based

organic semiconductors has not been examined by this near infrared region. A recent study showed that PCE
method.

of the C4-DPP-BP-based BHJ solar cell is high (5.2%)

For BP thin films, the majority of the signal compared with those of BP-based. Therefore, it is very
decays to zero with time constants of 0.5 ps and 6 ps. interesting to see whether the charge carrier dynamics
In the BP-based BHJ thin films, approximately 10% of in C4-DPP-BP:PC61BM BHJ film is different fromthe transient signal does not decay within 35 ps, BP or not. Furthermore attaching n-decyl (C10) groupindicating the survival of free charge carriers. For a to DPP unit induces the perpendicular orientation to
BP:PC61BM BHJ film, it is reported that the power the substrate (edge-on geometry), which is different
conversion efficiency (PCE) is only 0.02%. We from that of C4-DPP-BP of face-on geometry withconsidered that a slower recombination may be respect to the substrate. Consequently, PCE of theinvolve in the relaxation process of the charge carriers. C10-based OPV cell drops down to 0.19%. In contrast
Furthermore, we extend our studies to the charge to the large difference in PCE, similar dynamics arecarrierdynamics

tetrabenzoporphyrinofdiketopyrrolopyrrole-linked observed between C10-DPP-BP and C4-DPP-BP BHJ
thin

films

where

the films in the transient THz signals. We discuss thediketopyrrolopyrrole (DPP) unit has two n-butyl origin of similarity in terms of nature of the highgroups. In contrast to BP, C4-DPP-BP exhibits broad frequency response of photo-generated charge carriers.
and intense absorption, ranging from the visible and

Ⅱ-C.

MOLECULAR DYNAMICS IN THE TERAHERTZ FREQUENCY REGION IN
CONDENSED PHASES

Vibrational spectroscopy has been widely used to investigate structures, interactions and dynamics of moleculesand molecular complexes. The low-frequency region below several terahertz (THz; 1 THz = 33.3 cm-1)
corresponds to intermolecular modes of complexes and intramolecular modes with a weaker potential force
and/or larger reduced mass. Intermolecular interactions such as hydrogen bonding, van der Waals forces andcharge-transfer interactions play important roles in various chemical and biological processes. Moreover, thelow-frequency spectra also reflect molecular dynamics on a time scale from picoseconds to femtoseconds.
There has been dramatic progress in the generation and detection techniques of freely propagating THz
radiation in the past two decades. The examples of the generation technique include photoconductive switching,optical rectification, and the surface photocurrent of semiconductors. Because the pulse duration of the THz
radiation is in a sub-picosecond time region, it is possible to measure the electric field of the radiation bycoherent detection methods, which consequently allows us to conduct THz time-domain spectroscopy (TDS).
By THz-TDS the refractive index and extinction coefficient of a medium are obtained by measuring the phaseand amplitude of the radiation. THz-TDS is an attractive method for studying dynamics in condensed phaseswith time scales of sub-picoseconds and picoseconds. We have applied THz-TDS to investigate the lowfrequency dynamics of various kinds of condensed materials, including neat liquids and mixtures of liquids,
biological polymers, and conducting polymers.

20

A quantitative interpretation for the difference of found two critical aspects regarding the intensities ofterahertz spectra of DL- and L-alanine - origins of

the THz bands. We note that one is the cancelation of

IR intensities in THz spectroscopy

the transition dipole moments in the unit cell: even an

Feng Zhang, Keisuke Tominaga, Michitoshi individual molecule in a unit cell has a non-zero
Hayashi1, Masahiko Tani2transition dipole moment, a total transition dipole

1

National Taiwan University

moment of the unit cell is zero due to the cancellation

2

University of Fukui

of the contributions from the molecules. The second(J. Phys. Chem. B, 2021)

one is that these THz normal modes of DL- and L-

Motivated by explaining the THz spectra of DL- and alanine

aredominatedbytheintermolecular

L-alanine crystals recorded by Yamaguchi et al. (Appl.

translations, which are intrinsically infrared inactive if

Phys. Lett. 2005, 86 (5), 053903) we calculated thethe molecules are not polarized. Our analysis shows

THz spectra of DL- and L-alanine by solid-state that the IR intensities of these “almost pure”
density functional theory to perform a rigorous intermolecular translations are due to a subtle balance
discussion of IR intensities in THz spectroscopy. The between IR activities induced by the polarization
two crystals give rise to similar normal modes in the effect of translations and IR activities of the librations
5-80 cm-1 frequency range, and all the modes feature and intramolecular vibrations, which have marginal
predominantly intermolecular translations. We have presences in these normal modes.

Terahertz Spectroscopic Measurements and Solidstate

Density

Functional

Calculations

sum of the sharp bands and a broad background. Theseon broad spectral features are not usually observed at very

CH3NH3PbBr3 Perovskites -Short-Range Order of low temperatures for molecular crystals. The THz
spectrum at 10 K was calculated using solid-state DFT,

Methylammonium

Feng Zhang, Izuru Karimata1, Houng-Wei Wang2, and it turns out that the calculation failed to reproduce
Takashi Tachikawa, Keisuke Tominaga, Michitoshi the observed spectra. Here we propose a structural
Hayashi2, Tetsuo Sasaki3

model in which the MA cations can take two possible

1

Graduate School of Science, Kobe University

orientations at equal probability, which situation leads

2

National Taiwan University

to the coexistence of 16 unit-cell configurations in

3

Shizuoka University

terms of MA cations’ orientations. By calculating the(J. Phys. Chem. C, 2021)

THz modes associated with the 16 unit-cell

Temperature dependence of the vibrational absorption configurations under the periodic boundary conditions,spectra of MAPbBr3 (MA = methylammonium)

we have qualitatively captured the characteristics ofperovskites was studied in the frequency range from the observed THz spectra. Regarding the spatial
20 cm-1 to 200 cm-1 from 10 K to 293 K. The spectrum distributions of the 16 unit-cell configurations, ourat 10 K shows several sharp bands from 20 cm-1 to 120-1-1

cm , and there is a broad band centered at 155 cm .

study suggests that short-range ordered domains
should exist and the polarized domains can be in the

From 40 cm-1 to 120 cm-1 the spectrum looks like a majority.

21

Low-frequency Vibrational Modes of DMPG Lipid optimization reach a stable state, either a stable local
Bilayer Studied by Terahertz Spectroscopy and minimum or the global minimum of the potential
surface; so that no negative frequencies appear.

Solid-state Density Functional Theory

Feng Zhang, Tomoyo Andachi, Naoki Yamamoto1, Starting with a 1D model under the periodic boundary
Houng-Wei Wang2, Keisuke Tominaga, Michitoshi condition and successively approaching an actual 3D
Hayashi2

crystal structure, we have removed all the negative

1

Jichi Medical University

frequencies in the finally optimized crystal structure.

2

National Taiwan University

All the observed THz bands can be assigned. The(IRMMW-THz, 2021)

prominent peak, locating at 71 cm-1, has been

The structure-encoded low-frequency normal modes reproduced, and a few secondary peaks can find
(LFNM) of biomolecules have long been a curiosity ofconsistent correspondence with the calculated ones.

biophysicists. Functionally important motions are Note that discrepancies between the experimental
expected to be achieved through the nonlinear observation and theoretical calculation still exist in
coupling of LFNM. The LFNMs of biomolecules have terms of both the frequency and IR intensity. DMPG
been studied extensively using molecular dynamic represents, so far, the largest molecule crystal whose
simulations.

However,aconsistentagreement

THz spectrum has been satisfactorily reproduced. We

between experimentation and theory in terms of the did a preliminary analysis of the vibrational density of
LFNMs of biomolecules has been rarely achieved. states. The result shows that DMPG favors the energy
This work examines the LFNM of the lipid bilayer of regime of 0-200 cm-1, accommodating about 60% ofDMPG

throughaninterplay

betweenTHz all the normal modes distributing in the 0-600 cm-1

spectroscopy and solid-state density functional theory. frequency range. This observation implies the
For the calculations of such a large molecular tendency of the atomic motions in DMPG to establish
crystal, a vital challenge is to make the geometry a correlated relationship and form collective motions.

Hydration

DynamicsofThermo-responsive alkyl and hydrophilic amide groups influence the coil-

Polymers Investigated by Broadband Spectroscopy to-globule transition, but the detail of the molecular
Hikaru Ioka, Yuki Fujii, Lou Serafin Lozada, mechanism of the transition remains to be elucidated.
ChihiroHashimoto1,

Kaoru

Ohta,

KeisukeIn this work, we performed the broadband dielectricTominaga

spectroscopic measurements from the sub-GHz to1

THz frequency region and FT-IR measurements on the

Niihama National College of Technologyth(11 Asian Photochemistry Conference, 2021)

OH stretching band of the solutions to obtain

Poly(N-isopropylacrylamide) (PNiPA) and poly(N,N- information about dynamics and structures of thediethylacrylamide) (PdEA) in aqueous solutions hydration water around the solute molecules.
change their conformations from a hydrophilic coil-

The broadband dielectric spectra of aqueous

state to a hydrophobic globule-state with increasing

solutions of PNiPA, PdEA and their monomers weretemperature. The hydration state of the hydrophobic measured by a vector network analyzer and THz time-22

domain spectrometer. The temperature dependence of to the hydration water, bulk-like water, and the fast
the complex permittivity spectra was obtained from relaxation of these water. The dielectric strength of the
5℃ to the transition temperature. The complex hydration water decreases with increasing temperature,
permittivity spectra were assumed to consist of three which is consistent with a picture that the polymer
Debye relaxation components and one underdamped dehydrates when the temperature approaches to theoscillation. The three Debye components corresponds transition temperature.

II-D.

DEVELOPMENT OF WAVEFRONT SHAPING TECHNIQUE FOR ULTRAFAST OPTICALPULSESUltrafast nonlinear optical spectroscopy has become an indispensable tool to investigate various dynamical
processes in the condensed phase. Even though such spectroscopy is of great interest due to unique features ofthe structural and dynamical resolution, it is very difficult to perform the measurements in the scattering media.
Generally, when coherent light propagates in scattering media, the scattered light forms a destructive
interference pattern, so-called, “speckle”. Wavefront shaping by spatial light modulator was shown to control
light propagation through scattering media. One can use this method to control input wavefront to design the
output field, for example, to focus the light at a desired position. However, it still remains a challenge to control
both spatial and temporal properties of ultrashort pulses simultaneously in scattering media. We are developing
the wavefront and pulse-shaping techniques to control both the amplitude and phase of ultrashort pulses inscattering media.

Time-Reversal Focusing of Ultrashort Pulses the Fourier-transform limit. In this work, we develop
through Thin Scattering Media

new spatiotemporal wavefront shaping techniques to

Kaoru Ohta

focus ultrashort pulses at the target position through a(Optics Express, 2022)

thin scattering medium. Compared to other studies,

When ultrashort pulses propagate through a disordered one significant advantage of this method is that most
medium, scattering occurs and the intensity of the of the characterization of the spectrally-resolved
ballistic component decreases drastically. This limits transmission matrix and temporal profile of thethe applicability of time-resolved nonlinear optical ultrashort pulses can be done using single-beamspectroscopy and microscopy. The wavefront shaping geometry. An interferometer with external reference istechnique makes it possible to focus light through the necessary to measure the difference of the phasescattering medium; however, complete time-reversal profile between the focused and reference pulses.
of the ultrashort pulses (as short as 10 fs) is still a very Furthermore, the number of controllable phasechallenging problem. This is due to the in-depth components in the spectral domain is not limited bycharacterization and precise control needed for such the spectral correlations of the speckle patterns
pulses in the time domain in order to compress down because we used a pulse shaper in the time domain to23

optimize the temporal properties of the ultrashort extremely ultrashort pulses through thin scattering
focused pulse. Our new method provides increased media in order to achieve time-reversal focusing at theflexibility and precise control for manipulating target position.

II-E.

INTERMOLECULAR INTERACTIONS OF POLYMER STUDIED BY TERAHERTZ
SPECTROSCOPY

Low-frequency vibrational bands observed in the low-frequency Raman and terahertz (THz) spectra originate
from the higher-order structure, crystalline structure, and intermolecular interactions of polymer materials.
Therefore, THz and low-frequency Raman spectroscopy are unique techniques for analyzing higher-orderconformations and intermolecular hydrogen bonding in semi-crystalline polymers. However, the bandassignment of THz spectra of polymers has not been studied well. Therefore, it is necessary to develop bandassignment methods in order to establish THz spectroscopy as a powerful and unique method for exploring thestructure and physical properties of polymers.

VisualizationofInter-

Intramolecular blends during the isothermal melt crystallization. The

andInteractions in Poly(3-hydroxybutyrate)/Poly(L- peak position of ν(C=O) band, which reflects theDuringnature of the intermolecular interaction, shows that the

Isothermal Melt Crystallization Using Attenuatedintermolecular interactions between PHB and PLLA in

lacticacid)(PHB/PLLA)

BlendsTotal Reflection Fourier Transform infrared (ATR the miscible state (1733 cm-1) changes to the inter- and
FT-IR) Spectroscopic Imaging

intramolecular interaction (CH3∙∙∙O=C, 1720 cm-1)

H. Lu1, H. Sato, S. G. Kazarian1

within PHB crystal during the isothermal melt

1

Imperial College London

crystallization. Compared with spectroscopic images(Applied Spectroscopy, 2021)

obtained by plotting the distribution of absorbance ofInter-

andintramolecularinteractionsin spectral bands, which reveals the spatial distribution ofmulticomponent polymer systems influence their blend components, the approach of plotting the peakphysical and chemical properties significantly andposition of a spectral band reflects the spatial

thus have implications on their synthesis anddistribution of different intra- and intermolecular

processing. In the present study, chemical images wereinteractions.

With

the

processofobtained by plotting the peak position of a spectral meltcrystallization,

thedisappearance

isothermaloftheband from the data sets generated using in situ intermolecular interaction between PHB and PLLA
attenuated total reflection Fourier transform infrared and the appearance of the inter- and intramolecular(ATR FT-IR) spectroscopic imaging. This approach interactions within the PHB crystal were bothwas successfully used to visualize changes in intra- visualized through the images based on theandintermolecularinteractionsinpoly(3- observation of the band position. This work shows thehydroxybutyrate)/poly(L-lactic acid) (PHB/PLLA) potential of using in-situ ATR FT-IR spectroscopic

24

imaging to visualize different types of inter- or
intramolecularinteractions

betweenpolymermolecules or between polymer and other additives invarious types of multicomponent polymer systems.

Figure 1. Phase diagram and spectroscopic imagings.

Water-induced conformational changes in the water absorption. The position of the amide I band
powder and film of ε-poly(L)lysine studied bysuggests that the powder form of EPLHCl has a β-infrared and Raman spectroscopy

sheet structure, while the film has two types of β-sheet

M. Nochi, Y. Ozaki, H. Satostructures. Raman spectra of EPLHCl in the region(Spectrochimica Acta Part A, 2021)

1490–1440 cm−1 indicate that the EPLHCl film has a

In this study, we have investigated the water trans amide structure, unlike its powder form. Hence,
absorption-induced structural changes and thermal it is highly probable that the differences in the
behavior of ε-poly(L)lysine-hydrochloride (EPLHCl) secondary structures of the EPLHCl powder and filmin the powder and film samples using infrared (IR) and originate due to the twisting of the amide group
Raman

spectroscopy.

An

X-ray

diffraction induced by water absorption.

measurement reveals that the crystal structure of εpoly(L)lysine (EPL) is similar to that of the γ-crystalof nylon-6. The powder form of EPLHCl absorbs
water from the air and solidifies into a film (18% watercontent). The film does not transform into the powder
form with increasing temperature; it remains as a film,suggesting that the transformation from powder to film
is irreversible. The IR spectra in the amide I region of Figure 1. A schematic illustration of water-induced
the powder and film are distinctly different, indicating conformational changes in the powder and film of εthat the secondary structure of EPLHCl changes upon poly(L)lysine.

Study of Co-crystallization and Intermolecular (Macromolecules, 2021)
Hydrogen Bondings of Poly(glycolide-co-L-lactide) The co-crystallization and intermolecular hydrogen
Copolymers by Terahertz and Low-Frequency

bonding of poly(glycolide-co-l-lactide) [P(GA-co-

Raman Spectroscopy

LLA)]

A. Nishimae, H. Sato

differential scanning calorimetry (DSC), wide-angle

25

copolymers

have

been

studiedusing

X-raydiffraction(WAXD),

small-angle

X-ray

behaviors of the shifts between the PGA homopolymer

scattering, and infrared (IR), terahertz, and low-and P(GA-co-LLA) copolymers are due to thefrequency Raman spectroscopy. The DSC and WAXD presence of PLA, and the co-crystallization can induce
results confirm that the melting point of the P(GA-co- the formation of new intermolecular interactions
LLA) copolymers decreases linearly and the spacing between PGA and PLA. The temperature dependenceof the (110) and (020) planes expands as the of the IR bands of the P(GA-co-LLA) copolymers inconcentration of polyglycolic acid (PGA) in the the C═O, CH2, and C–O–C stretching regions
copolymers decreases. Furthermore, the lamellar suggests that the new intermolecular interaction of
thickness of the P(GA-co-LLA) copolymers increases C═O···H3C

isformedbecause

of

the

co-

with an increase in the concentration of polylactic acid crystallization of the P(GA-co-LLA) copolymers and(PLA), which is the same as that of poly(3- the C–H···O(ether) hydrogen bonding in the PGA
hydroxybutyrate-co-3-hydroxyvalerate),aco- homopolymer is maintained in the P(GA-co-LLA)

crystallized copolymer. These results indicate that copolymers. Therefore, P(GA-co-LLA) copolymers
P(GA-co-LLA) copolymers are co-crystallized. The that form co-crystallization have two types ofcopolymers show a terahertz band at approximately 75

hydrogen bondings: C═O···H3C and C–H···O(ether)–1

cm and Raman bands at approximately 130 and 80 hydrogen bondings.
cm–1. The corresponding terahertz band at 75 cm–1 andRaman bands at 130 and 80 cm–1 of the PGA
homopolymer show a shift to a relatively low
frequency during the heating process because ofthermal expansion. However, the terahertz band of theP(GA-co-LLA) copolymers at approximately 75 cm–1
shifts to a relatively high wavenumber, and their
Raman bands at approximately 130 and 80 cm–1 do notshow any shift despite the expansion of the crystal
lattice of the P(GA-co-LLA) copolymers with the

Figure 1. THz spectra of PGA and P(GA-co-LLA)

increasing concentration of PLA. The different copolymers.

Solvent Effect on Competition Between Weak and4

Kwansei Gakuin University

Strong Interactions in Phenol Solutions Studied by (Phys. Chem. Chem. Phys., 2021)
Near-infrared Spectroscopy and DFT Calculations

Near-infrared (NIR) spectra of phenol in a series of

M. A. Czarnecki,1 Y. Morisawa,2 Y. Katsumoto,3 T. non-aromatic and aromatic solvents were recorded to
Takaya,4 S. Singh,1 H. Sato and Y. Ozaki

study the competition between various types of solute–

1

University of Wrocław

solute and solute–solvent interactions. Depending on

2

Kindai University

the phenol concentration, the free OH and OH

3

Fukuoka University

involved in the OH⋯OH interactions in the dimers and26higher associates are present in cyclohexane solutions. in the benzene derivatives. This observation obtained
On the other hand, free OH does not appear in Cl- from the NIR spectra is in line with the results of thecontaining solvents since at a low phenol content the theoretical calculations (DFT). A clear correlation
OH groups participate in the OH⋯Cl interactions. In appears between the number of methyl groups in
CCl4 and tetrachloroethylene this interaction is weak, aromatic solvents and the population of the free OH
while in chlorobenzene the strength of this interaction groups. The methyl groups are steric hindrances andis higher. In the aromatic solvents the solute–solute impede the formation of the OH⋯OH and OH⋯π
OH⋯OH interactions compete with the solute–solvent interactions. Our results suggest the presence ofOH⋯π and aromatic CH⋯OH ones. Consequently, the aromatic CH⋯OH solute–solvent interactions, notdegree of self-association of phenol in aromatic observed in previous studies. NIR spectroscopy
solvents is smaller than that in non-aromatic ones. The appears to be a powerful tool for exploration of freestrength of the OH⋯π interactions increases withand weakly-bonded OH groups.

growing electron-donating ability of the substituents

Correlation of physical aging and glass transition relaxation magnitude with temperature; (2) 70oC ≤ Tage
temperaturesinultrathinpolystyrene

films ≤ 110oC, a slow decrease in thickness with time and an

supported on SiO2

increase in relaxation magnitude with temperature; (3)T. Sharma,1 Y. Nishio,1 Y. Tamano,1 H. Sato, I. Tage > 110 oC, an increase in thickness with time due toTakahashi1

dewetting of PS films deposited on SiO2. Such an

1

Kwansei Gakuin University

interesting relaxation behavior can arise from the(Polymer, 2021)

enhanced dynamics at the surface and reducedThis study examined the effects of the aging mobility at the interface inherent in ultrathintemperature (Tage) on structural relaxation in ultrathin- supported films. Two distinct Tgs peculiar to ultrathin
supported polystyrene (PS) films with thickness films were confirmed. The lower Tg has not been
~0.2Rg. X-ray reflectivity and differential scanning

reported for supported PS films. The relaxation

calorimetry were used to evaluate the glass transition summarized above revealed a strong correlation withtemperature (Tg) of ultrathin PS and bulk PS, the Tg values The de Gennes modified sliding motion
respectively. The ultrathin films in their confined state model was applied to explain the correlation withshowed anomalous thickness relaxation behaviors that relaxation dynamics.
could be classified into three types: (1) Tage ≤ 60oC , aslow increase in thickness with time and a decrease in27

III Terahertz Material Physics Laboratory
III-A.

HIGH FIELD ELECTRON SPIN RESONANCE (ESR) STUDIES OF QUANTUM SPINSYSTEMS

The quantum effects and the spin frustration effects prevent long-range order due to strong quantum
fluctuation and frustration. Their ground states at low temperature are attractive issues in field of solid statephysics. High-frequency high-field ESR is a powerful spectroscopic method to investigate the ground stateand lower excited state of the system, because the ESR observes directly the magnetic excitation. These studyof quantum spin and spin frustration systems has been extended recently. In the quantum spin systems, newphases have been discovered in S=1/2 1D Heisenberg antiferromagnetic chains with staggered fields
associated with the Oshikawa-Affleck theory and in S=1/2 1D Heisenberg antiferromagnetic chains with atriangular lattice structure perpendicular to the chain associated with both of the magnetic anisotropy andeffective spin size. In addition, new concepts related to the spin texture, such as Z2 vortices and skyrmion
lattices, have been discovered in spin frustrated systems. We are continuing detailed research on quantum
spin systems. The appearance of breather, soliton and antisoliton modes are expected in wide frequency-field
ESR measurements of S=1/2 Heisenberg antiferromagnetic chain with staggered g-tensor and D vector
system. Such peculiar behavior has been found in pure system KCuMoO4(OH) by our group and doped
system CuGeO3 by S. Demishev, which have been performed under the joint research program of Molecular
Photoscience Research Center, Kobe University. We also continue to study three-dimensionally correlated
frustrated magnets GeCo2O4 and 4f-electron magnets CeB6. Research on CeB6 magnetic has been performed
under a joint research project. We have made many achievements in the study of triangular lattice
antiferromagnets through our high pressure ESR measurements and cooperation with theorists. High pressure
ESR measurements are one of the features of our center. The appearance of Higgs amplitude modes in the
S=1/2 dimer system KCuCl3 under high magnetic field and high pressure has been found theoretically using
extended spin-wave theory by M. Matsumoto. In the S=1/2 triangular lattice antiferromagnet CsCuCl3, wehave experimentally found that the exchange interaction and magnetic anisotropy change drastically underapplied pressure. Collaborator D. Yamamoto have succeeded in explaining this behavior theoretically by aneffective change in the spin size in the spin chain. In a joint Japanese-German project, ESR measurements ofthe two dimer system CuVOF4(H2O)6·H2O, which consists with S=1/2 spins of Cu2+ and V4+ ions, has been
performed. ESR revealed the gap of two dimer system. M. Akaki in our group is strongly performing highfield ESR measurements of multiferroics materials, dichroic Pb(TiO)Cu4(PO4)4, and a quasi-one-dimensional
spin system BaCo2V2O6, and clarified their spin states. H. Kawamura, a visiting professor who came to ourgroup in 2020, is theoretically conducting research on spin textures related to spin frustration. Kawamura's
collaborator, K. Aoyama, theoretically applied the spin texture of the classical Heisenberg antiferromagnetic
Hedgehog lattice to a breathing pyrochlore lattice. K. Uematsu shows that spin frustration induces quantum
spin liquid behavior in the S=1/2 random-bond Heisenberg antiferromagnet on the zigzag chain. And also
Kawamura's collaborators Dr. Tomiyasu and Dr. Mizuta have observed the Z2 vortex and found its causethrough experimental and theoretical studies of inelastic neutron scattering in the triangular-lattice28

Heisenberg antiferromagnet NaCrO2. K. Mitsumoto in our group showed the Scarmion crystal in twodimensional triangular lattices and clarified the replica symmetry of the Scarmion crystal.
For other joint researches, high-field ESR and the magnetic susceptibility measurements of many
materials have been performed to obtain magnetic information. And we also have joint research withtheoretical groups for obtaining experimental parameters from quantum calculations. In total, our joint
researches have been performed with 18 groups, and we have organized one scientific meeting with joint
research groups.
Our group has received research and paper awards again. H. Ohta has received research achievement
award from the Japan Society of Infrared Science and Technology. Y. Kitahara, S. Hara, T. Sakurai, S. Okubo,
H. Ohta have received paper award from the Japan Society of Infrared Science and Technology. M. Akaki
has received Young Scientist Award of the Physical Society of Japan. N. Nagawasa has received ResearchPresentation Excellence Award from the Japan Society of Infrared Science and Technology.
H. Ohta is becoming the President of the Japan Society of Infrared Science and Technology (20212023). H. Ohta is also acting as the Advisory Council of APES (Asia-Pacific EPR/ESR Society), and theCouncil Member of the Society of Electron Spin Science and Technology (SEST), the International EPR
Society (IES) Associate Editor Asia-Pacific, a board member of Yukawa Memorial Foundation and thechairman of the Mochizuki Foundation in Yukawa Memorial Foundation. H. Ohta is the Local Organizing
Committee Chair and S. Okubo is the member of the fund-raising committee of the ISMAR-APNMR 2021
which will be held in Aug., 2021 as the online conference.
Moreover, in order to strengthen the pulsed magnetic field researches in the western Japan region, we
have been continuing the activities of The KOFUC (Kobe-Osaka-Osaka Prefecture-Fukui Universities
Centers) Network since 2014.

Staggered Field in Quantum Antiferromagnetic S

frequency EPR brings to light physics still actual for= 1/2 Spin Chain Probed by High‐Frequency EPR

one-dimensional S = 1/2 quantum spin chains and(the Case of Doped CuGeO3)

covering a vast area from disorder-driven quantum

S. V. Demishev1,2, A. V. Semeno1, and H. Ohta3

critical phenomena to a new type of magnetic

1

Prokhorov General Physics Institute of the Russian

oscillations. It is shown that a key opening the door for

Academy of Sciences

a better understanding of this field of research is the2

National Research University Higher School of

Oshikawa and Affleck (OA) theory and, especially,

Economics

following from it the universal link between the line

3

Molecular Photoscience Research Center, Kobe

width and g factor. The most puzzling problem

University

appears around the staggered field, which contributes(Appl. Mag. Res., 2021)

to different physical properties and serves as a driving

The flashback of the investigation of CuGeO3 doped

force in the onset of anomalous growth of the linewith magnetic impurities carried out by high-width and g factor at low temperatures. Accent is made29

on unsolved problems still providing a challenge forneither in OA theory nor within the framework of thethe theoretical explanation, including the genesis ofsemi-classical magnetization motion, is described in

the staggered field in doped systems, the contribution

detail. This experimental finding poses the mostof the staggered magnetization to the integrated

difficult case and a touchstone for theory, as long as

intensity, and spin susceptibility of a Griffiths phasethe corresponding modes of magnetic oscillations may

and its magnetic properties on the nanoscale. A new

be likely treated as violating Landau–Lifshits equation

type of magnetic oscillations, having explanationof motion.

THz ESR Study of Peculiar Co Pyrochlore System

antiferromagnetic phases, AF1 and AF2, below TN.

GeCo2O4 Using Pulsed High Magnetic Field

Moreover, a wide magnetic field range of ESR study

S. Okubo1,2, H. Ohta1,2, T. Ijima2, T. Yamazaki2,

using a single crystal at 1.8 K also revealed various

W-M. Zhang1, S. Hara3, S. Ikeda4, H. Oshima5, M.

field-induced phases due to the competition between

Takahashi6, K. Tomiyasu7, T. Watanabe8

the spin–lattice coupling and the spin frustration.

1

Molecular Photoscience Research Center, Kobe

Critical field resonances were observed at 5.0 T, 8.6 T,

University

and 11.0 T for B // [111] and 5.1 T, 7.7 T, 11.2 T, and2

Graduate School of Science, Kobe University

13.0 T for B // 110] at 1.8 K. Although it became

3

Center for Supports To Research and Educationdifficult to observe ESR above 86 K, the g-values ofActivities, Kobe University

Co2+ ions were estimated to be g[111] = 3.34 and g[110]4National Institute of Advanced Industrial Science and= 3.27 for [111] and [110], respectively, from theTechnology

observed ESR mode above the saturation field at 1.8

5

Institute of Material Science, University of Tsukuba

K. Detailed frequency-field diagrams of the ESR

6Faculty of Pure and Applied Sciences, University ofmodes at 1.8 K suggested the existence of spin–lattice

Tsukubacoupling energy of 250 GHz (= 1.03 meV = 12 K) at

7

Department of Physics, Tohoku University

the critical field resonances. The spin gap mode in the8

Department of Physics, College of Science andfrequency-field diagram at 1.8 K showed excitation

Technology, Nihon University

energies of E[111] = 1004 GHz (= 4.15 meV = 48 K)(Appl. Mag. Res., 2021)

and E[110] = 1044 GHz (= 4.32 meV = 50 K) for [111]THz electron spin resonance (ESR) measurements ofand [110], respectively. These results will be

the spinel compound GeCo2O4, which consists of the

discussed in connection with the di-tetramer model

Co2+ pyrochlore structure, were performed. The

suggested previously.

temperature dependence measurements revealed new

Heavy Fermion Metal CeB6 in SubTHz and THz

A.V. Semeno1, S. Okubo2, H. Ohta2, and S. V.

Range: The Electron Spin Resonance and Neutron

Demishev3

Scattering Studies

30

1

Prokhorov General Physics Institute of Russian

appeared since the discovery in this material the ESR,

Academy of Sciences

which is specific to antiferroquadrupole (AFQ) phase2

Molecular Photoscience Research Center, Kobe

and is missing in the paramagnetic phase. In the

University

present review, we have brought together electron spin

3

National Research University Higher School ofresonance and inelastic neutron scattering data, which

Economics

allowed obtaining most detailed structure of the(Appl. Mag. Res., 2021)

magnetic resonance modes in the AFQ phase in a

Cerium hexaboride attracts attention of solid-state

wide-frequency range up to 0.6 THz. It is shown that

community for almost 50 years. Nowadays, thisapart paramagnetic resonance main mode withmaterial is considered as a unique example of a systemhomogeneous precession of the magnetization, therewith orbital ordering resulting in formation of low-

are antiferromagnetic resonance modes as well, sometemperature magnetic phase with quadrupolar order,of them existing in the AFQ phase. Analysis of the g

the so-called antiferroquadrupole phase. In crystal

factors demonstrates that available theories based onelectric field 4f1 state of Ce3+ splits into Γ7 doublet andΓ8 ground state are facing difficulties with accounting

Γ8 quartet, the latter is believed to be the ground state,experimental data, thus providing a challenge foras long as just Γ8 allows quadrupolar effects. An

developing of a theory correctly describing dynamic

additional tool for studying rich physics of CeB6

magnetic properties of this interesting material.

First ESR Detection of Higgs Amplitude Mode and6

Analysis with Extended Spin‐Wave Theory inTechnology

Dimer System KCuCl3(Appl. Mag. Res., 2021)

M. Matsumoto1, T. Sakurai2, Y. Hirao3, H. Ohta4,

KCuCl3 is known to show a quantum phase transition

Y. Uwatoko5, and H. Tanaka6from the disordered to antiferromagnetically ordered

1

Department of Physics, Faculty of Science, Shizuoka

phases by applying pressure. There is a longitudinal

University

excitation mode (Higgs amplitude mode) in the2

DepartmentofPhysics,

Tokyo

InstituteofResearch Facility Center for Science and Technology, vicinity of the quantum critical point in the ordered

Kobe University

phase. To detect the Higgs amplitude mode, high-3

Graduate School of Science, Kobe University

pressure ESR measurements are performed in KCuCl3.

4

Molecular Photoscience Research Center, Kobe

The experimental data are analyzed by the extended

University

spin-wave theory on the basis of the vector spin

5

Institute for Solid State Physics, The University ofchirality. We report the first ESR detection of theTokyo

Higgs amplitude mode and the important role of theelectric dipole described by the vector spin chirality.

31

Continuous control of classical-quantum crossover

determined and fixed at the chemical synthesis, whichby external high pressure in the coupled chain

makes it challenging to control the amount of quantum

compound CsCuCl3

correlations. We propose and demonstrate a method

D. Yamamoto1,2, T. Sakurai3, R. Okuto4, S. Okubo5, for active control of the classical-quantum crossover
H. Ohta5, H. Tanaka6, and Y. Uwatoko7

in magnetic insulators by applying external pressure.

1

Department of Physics, Nihon University

As a concrete example, we perform high-field, high-2

Department of Physics and Mathematics, Aoyamapressure measurements on CsCuCl3, which has the

Gakuin University

structure of weakly-coupled spin chains. The

3

Research Facility Center for Science and Technology, magnetization process experiences a continuous

Kobe University

evolution from the semi-classical realm to the highly-

4

Graduate School of Science, Kobe University

quantum regime with increasing pressure. Based on

5

Molecular Photoscience Research Center, Kobe

the idea of "squashing” the spin chains onto a plane,

University

we characterize the change in the quantum correlations

6

DepartmentofPhysics,

Tokyo

Instituteofby the change in the value of the local spin quantum

Technology

number of an effective two-dimensional model. This

7

Institute for Solid State Physics, The University ofopens a way to access the tunable classical-quantumTokyocrossover of two-dimensional spin systems by using(Nature Communications, 2021)

alternative systems of coupled-chain compounds.

In solid materials, the parameters relevant to quantum
effects, such as the spin quantum number, are basicallyNonreciprocal
electronspinlineardichroism

resonance

observed

spectraofin(Phys. Rev. Research 3, 2021)

the

It

is

known

that

magnetic

excitations

inmagnetoelectric multiferroic Pb(TiO)Cu4 (PO4 )4magnetoelectric multiferroics can be induced by the

Mitsuru Akaki1,2,* Kenta Kimura3, Yasuyuki

oscillation

Kato4, Yuya Sawada2, Yasuo Narumi2, Hitoshi

electromagnons, which often cause nonreciprocal

Ohta1, Tsuyoshi Kimura3, Yukitoshi Motome4, andopticalMasayuki Hagiwara2

excitations

1

Molecular Photoscience Research Center, Kobe

Pb(TiO)Cu4(PO4)4 were obtained in wide ranges of

University

magnetic fields up to 50 T and frequencies below 2

2

Center for Advanced High Magnetic Field Science,THz. Some of the observed resonance modes were

Graduate School of Science, Osaka University

reproduced qualitatively by a numerical analysis based

3

Department of Advanced Materials Science, The

on the generalized spin-wave theory. Moreover, weUniversity of Tokyo

found that electron spin resonance (ESR) signals on

4

Department of Applied Physics, The University ofsome of the modes can be modulated by applying anTokyoelectric field. This result implies the presence of

32ofelectric

phenomena.
inthepolarization,

Energydiagrams

magnetoelectric

calledofthemultiferroic

nonreciprocal linear dichroism on the ESR signals in
Pb(TiO)Cu4(PO4)4.

Optical selection rules of the magnetic excitation in

10

the

and Technology

S=1/2

one-dimensional

Ising-like

National Institute of Advanced Industrial Science

antiferromagnet BaCo2V2O8(Phys. Rev. B., 2022)

S. Kimura1, H. Onishi2, A. Okutani3, M. Akaki4, Y.

In this study, we clarify the selection rules of optical

Narumi5, M. Hagiwara5, K. Okunishi6, K. Kindo7,transitions from the ground state to the magnetic

Z. He8, T. Taniyama9, and M. Itoh10

excited states in the quasi-one-dimensional quantum

1

Institute for Materials Research, Tohoku University

Ising-like antiferromagnet BaCo2V2O8 with spin

2

Advanced Science Research Center, Japan Atomic

S=1/2 using the high-field electron spin resonance

Energy Agency

measurement

3

Research Center for Development of Far-Infrared

electromagnetic waves. We demonstrate that theRegion, University of Fukui

unconventional magnetic excitation via the pair4

Molecular Photoscience Research Center, Kobe

creation of quasipaticles at wave numbers qz = π/2 andUniversity

π in the field-induced quantum critical state can5Center for Advanced High Magnetic Field Science,couple with both oscillating magnetic and electricwithilluminating

polarized

Graduate School of Science, Osaka University

fields. Our density matrix renormalization group6

Department of Physics, Niigata University

calculations indicate that the observed selection rules

7

Institute for Solid State Physics, The University of

can be explained by two- and four-fold periodical spinTokyointeractions, originating from the screw chain

8

State Key Laboratory of Structural Chemistry, Fujian

structure

Institute of Research on the Structure of Matter,magnetoelectric coupling between spins and electric

Chinese Academy of Sciences

dipoles.

9in

BaCo2V2O8,

inadditiontotheDepartment of Physics, Nagoya University

Anomalous magnetic exchange in a dimerized2

quantum magnet composed of unlike spin species

Durham University

S. P. M. Curley1, B. M. Huddart2, D. Kamenskyi3, 4,

3M. J. Coak1, R. C. Williams1, S. Ghannadzadeh5, A.

Correlations and Magnetism, Institute of Physics,

Centre for Materials Physics, Department of Physics,
Experimental Physics V, Center for Electronic

Schneider6, S. Okubo4, T. Sakurai4, H. Ohta4, J. P.

University of Augsburg

Tidey7, D. Graf8, S. J. Clark2, S. J. Blundell5, F. L.

4

Molecular Photoscience Research Center, Kobe

Pratt9, M. T. F. Telling9, T. Lancaster2, J. L.

University

Manson10, and P. A. Goddard1

51

Oxford University

Department of Physics, University of Warwick

Department of Physics, Clarendon Laboratory,33

6

Experimental Physics VI, Center for Electronic

deter- mined from magnetometry and electron-spin

Correlations and Magnetism, Institute of Physics,

resonance measurements. The results of density

University of Augsburg

functional theory (DFT) calculations are consistent

7

Department of Chemistry, University of Warwickwith the experimental results. The DFT calculations

8

National High Magnetic Field Laboratory, Florida

predict antiferromagnetic coupling along all nearest-

State University

neighbor bonds, with the magnetic ground state

9

ISIS Facility, Rutherford Appleton Laboratorycomprising spins of different species aligning

10

Department of Chemistry and Biochemistry, Eastern

antiparallel to one another, while spins of the same

Washington University

species are aligned parallel. The magnetism in this(Phys. Rev. B., 2021)

system cannot be accurately described by the overlap

We present here a study of the magnetic properties ofbetween localized V orbitals and magnetic Cu orbitals

the antiferromagnetic dimer material CuVOF4(H2O)6·

lying in the Jahn-Teller (JT) plane, with a tight-

H2O, in which the dimer unit is composed of two

binding model based on such a set of orbitals

different S = 1/2 species, Cu(II) and V(IV). An applied

incorrectly predicting that interdimer exchange should

magnetic field of μ0Hc1 = 13.1(1) T is found to close

be dominant. DFT calculations indicate significant

the singlet-triplet energy gap, the magnitude of whichspin density on the bridging oxide, suggesting instead

is governed by the antiferromagnetic intradimer J0 ≈an unusual mechanism in which intradimer exchange

21 K, and interdimer J'≈ 1 K, exchange energies,

is mediated through the O atom on the Cu(II) JT axis.

Effects of spin-lattice coupling and a magnetic field

SLC, the bond-phonon and site-phonon models. It is

in classical Heisenberg antiferromagnets on thefound by means of Monte Carlo simulations that inbreathing pyrochlore latticeboth models, the 1/2 plateau shows up in the

K. Aoyama1, M. Gen2 and H. Kawamura3

magnetization curve being relatively robust against the1

Department of Earth and Space Science, Graduate

breathing bond alternation, although magnetic long-

School of Science, Osaka University

range orders (LRO’s) are realized only in the site-

2

Department of Advanced Materials Science, The

phonon model. In the bond-phonon model, additional

University of Tokyo

further neighbor interactions are necessary to induce a3

Molecular Photoscience Research Center, Kobe

magnetic LRO. In the site-phonon model, it is also

University

found that in addition to the low-field, middle-field 1/2(Phys. Rev. B., 2021)

plateau, and high-field phases appearing on both theWe theoretically investigate spin-lattice coupling

uniform and breathing pyrochlore lattices, various(SLC) effects on the in-field ordering properties oftypes of unconventional phases which can be viewed

classicaltheas LRO’s in units of tetrahedron are induced by thebreathing pyrochlore lattice. Here, we use the twobreathing bond alternation just below the 1/2 plateau

possible simplified models describing the effect ofand the saturation field. The occurrence of these

local lattice distortions on the spin ordering via thetetrahedron-based orders could be attributed to the

Heisenberg

antiferromagnets

on34

nature characteristic of the breathing pyrochlore lattice, tetrahedra. Experimental implications of our result arei.e., the existence of the nonequivalent small and large

also discussed.

Replica

Hamiltonian and the ordered state are entirely regular.

symmetrybreaking

in

the

RKKY

skyrmion-crystal system

In the RSB SkX phase, the triple-q SkX state

K. Mitsumoto and H. Kawamura

macroscopically coexists with the single-q state, even

(Phys. Rev. B., 2021)

though these ordered states cannot be transformed via

We study the RKKY Heisenberg model on a three-anydimensional stacked-triangular lattice under magnetic

thermodynamic limit, the free energies of these states

fields by extensive Monte Carlo simulations to get

are degenerate whereas the free-energy barrier

insight into the chiral-degenerate symmetric skyrmion

between the states diverges, breaking the ergodicity. A

crystal (SkX) in centrosymmetric metallic magnets.

similar RSB is also observed in the RSB double-q

The triple-q SkX and the double-q states are realized,

phase where the double-q state macroscopically

together with the single-q state. We find an unexpected

coexists with the single-q state. Experimental

phenomenon of the replica-symmetry breaking (RSB)

implications are discussed.

Hamiltonian-symmetry

operation.

In

the

well known in glassy systems, although the

Frustration-induced quantum spin liquid behavior

with the competing nearest-neighbor and next-nearest-inneighbor antiferromagnetic interactions, J1 and J2, by

the

s

=

1/2

random-bondHeisenberg

antiferromagnet on the zigzag chainmeans of the exact diagonalization, density-matrix

K. Uematsu1, T. Hikihara2, and H. Kawamura3

renormalization-group and Hams–de Raedt methods.

1

Department of Earth and Space Science, Graduate

We find that, on increasing the frustration J2, theSchool of Science, Osaka University

gapless

2

Faculty of Science and Technology, Gunma

unfrustrated model with J2 = 0, the unfrustrated

University

random-singlet (RS) state, exhibits a phase transition

3

Molecular Photoscience Research Center, Kobe

into different gapless nonmagnetic state, the frustrated

University

RS state. This frustrated RS state in 1D has properties(J. Phys. Soc. Jpn., 2021)

quite similar to the randomness-induced QSL-like

Recent studies have revealed that the randomness-state recently identified in 2D and 3D frustrated

induced quantum spin liquid (QSL)-like state ismagnets exhibiting the T-linear low-temperature (T)stabilized in certain frustrated quantum magnets inspecific heat, while the unfrustrated RS state is more

two and three dimensions. In order to clarify the natureor less specific to the unfrustrated 1D systemof this gapless QSL-like state, we investigate both

exhibiting the ∼1=∣logT∣3 low-T specific heat.

zero- and finite-temperature properties of the random-

Universal features and the robustness againstbond one-dimensional (1D) s = 1/2 Heisenberg model

perturbations of the frustrated RS state are emphasized.

35

nonmagnetic

state

stabilized

in

the

Spin Dynamics Simulation of the Z2-vortex

5Fluctuations

University

Y. P. Mizuta1, K. Aoyama2, K. Tomiyasu3, M.

(J. Phys. Soc. Jpn., 2022)

Matsuura4, and H. Kawamura5

Motivated by the recent quasi-elastic neutron

1

Graduate School of Engineering Science, Osaka

scattering experiment, we extend the spin-dynamics

University

simulation on the triangular-lattice Heisenberg

2

Department of Earth and Space Science, Graduate

antiferromagnet, to observe a sharp central peak of its

School of Science, Osaka University

energy width ∼0.001J (J the exchange coupling) of the3

Nissan ARC Ltd.

Z2-vortex origin, consistently with the experiment.

4

CROSS Neutron Science and Technology Center

Molecular Photoscience Research Center, Kobe

Skyrmion crystal in the RKKY system on the two-

containing neither the nesting nor the many-bodydimensional triangular latticeinteraction. The SkX phase is stabilized under applied

K. Mitsumoto and H. Kawamura

fields where the frustration associated with the(Phys. Rev. B., 2022)

oscillating nature of the RKKY interaction and the

We study the ordering properties of the isotropic

emergent many-body interactions generated by

RKKY Heisenberg model on the two-dimensional

thermal fluctuations play important roles. Replica(2D) triangular lattice by extensive Monte Carlosymmetry breaking, reported in our recent paper on thesimulations to get insights into the chiral-degenerate

3D RKKY model [K. Mitsumoto and H. Kawamura,skyrmion crystal (SkX) of metallic magnets. Our

Phys. Rev. B 104, 184432 (2021)], turns out to be

Hamiltonian contains only the spin-quadratic RKKY

absent in the present 2D model. Implications to theinteraction derived from the spherical Fermi surface,

SkX formation mechanism are discussed.

Observation of topological Z2 vortex fluctuations in6

the frustrated Heisenberg magnet NaCrO2

University

K. Tomiyasu1,2, Y. P. Mizuta3, M. Matsuura4, K.

(arXiv., 2021)

Aoyama5, and H. Kawamura6

Spin fluctuations in the triangular-lattice Heisenberg

1

Department of Physics, Tohoku University

antiferromagnet NaCrO2 are investigated by means of2

Nissan ARC Ltd.

quasi-elastic neutron scattering with high energy

3

Graduate School of Engineering science, Osaka

resolution and wide energy band. Three components

Molecular Photoscience Research Center, Kobe

Universityof spin fluctuations, which are different in temperature

4

CROSS Neutron Science and Technology Center

dependence and time scale, are captured. The slowest

5

Department of Earth and Space Science, Graduate

component is described by a very sharp quasi-elastic

School of Science, Osaka University

scattering with energy width of approximately 0.01
meV (∼ 0.001J, where J the exchange coupling),

36

which is significant in the middle-temperature range

checked against the Z2 vortex theory to arrive at aof 30-40 K and goes away both in the lower and higher

natural explanation, indicating that the elusive Z2

temperature ranges. The experimental features arevortex fluctuations are finally detected directly.

III-B.

DEVELOPMENT OF NOVEL ESR TECHNIQUES IN THE THz REGION USINGTHERMAL AND PHOTOMIXING DETECTION METHODS

Thermal detection of ESR signal is a powerful technique for sensitive detection of small-volume samples. In
this technique, heat relaxation of a sample accompanied by ESR absorption is converted to temperature
increase of a thermometer attached to the sample. We developed a novel thermal detection technique in theterahertz region for protein solution sample. This technique was first applied to hemin, which is known as amodel substance of hemoproteins, in order to evaluate its performance. We successfully observed ESR
signals characteristic for ferric ions with a substantial signal-to-noise ratio. As a next step, a solution sample
of hemoprotein will be tested in the future.
We also developed a force-detected ESR technique using a high-power terahertz source, gyrotoron,
installed at Fukui University. This technique is suitable for low-concentration spin systems such as
metalloproteins. The measurements system was optimized at Fukui University with helps of Dr. Ishikawa
and Prof. Mitsudo. This technique is promising for future applications to a solution sample of metalloproteinsat room temperature.
We also developed a frequency-domain ESR spectroscopy technique using photomixing devices. By
combining an active phase modulation technique, high spectral resolution as high as 1 MHz was attained.
With this technique, we successfully observed narrow ESR signals of a mixed powder of DPPH andTEMPOL radicals. This technique was also applied to a single crystal of NiO, and antigerromagnetic
resonance (AFMR) signals were clearly observed. We also investigated the magnetic field dependence of the
AFMR mode in three different field orientations for the first time. In particular, it was found that the AFMR
mode split into two branches in the <111> axis. These results will be analyzed taking the magnetic domain
structure into account.
Collaborative researches with Dr. Horitani at Saga University and with Dr Inanami at Hokkaido
University were carried out. H. Takahashi continuously conducted the research project from JST-PRESTO's
program "Thermal Science and Control of Spectral Energy Transport", in which the heat transport ofmagnetic materials was studied by high-frequency ESR spectroscopy.
Mr. Shoji gave an oral talk entitled “High-resolution frequency-domain terahertz spectroscopy and its
application to electron paramagnetic resonance” at International Conference on Infrared, Millimeter, andTerahertz Waves (IRMMW-THz 2021).

37

Mechanically Detected Terahertz Electron Spindescribed to demonstrate its usability as a novel

Resonance

methodology for obtaining microscopic insights into

E. Ohmichi1, T. Okamoto1, H. Takahashi2, and H.

local electronic structures. Using micro-mechanicalOhta2

devices, the sensitivity to a small-volume sample is1

Graduate School of Science, Kobe University

greatly enhanced even for a cavityless setup.

2

Molecular Photoscience Research Center, Kobe

Moreover, there are plenty of options in the setup of

University

MDESR, including detection modes, mechanical(Appl. Mag. Res., 2021)

devices, and detection techniques. ESR spectroscopy

In this review, mechanically detected electron spinof single-crystalline, powder, and frozen solution

resonance (MDESR) in the terahertz (THz) region is

samples in the THz region are demonstrated.

Field-angle-dependent multi-frequency electronof millimeter and submillimeter waves. Under highspin resonance spectroscopy in submillimeter wave

vacuum conditions, a cantilever-shaped device detects

range based on thermal detection

ESR absorption of a mounted sample as a temperature

H. Takahashi1,2,3, T. Sakurai4, E. Ohmichi3, H.

difference in its beam direction. Despite the simple

Ohta1,3

experimental setup, the spin sensitivity of the order of1

Molecular Photoscience Research Center, Kobe

1012 spins/G was achieved at 10 K. The developed

University

sample stage is small enough to be used in a 10 T split-

2

JST-PRESTO

pair superconducting magnet with a bore of 25 mm,

3Graduate School of Science, Kobe University

enabling

4

Research Facility Center for Science and Technology, measurements at multi-frequencies above 500 GHz.

precisefield-angle-dependent

ESR

Kobe University

We demonstrate its usefulness by studying the field-(Rev. Sci. Instrum., 2021)

angle dependence of the excitation energy of the dimer

We report the thermally detected electron spin

triplet state in the Shastry–Sutherland magnet

resonance (ESR) spectroscopy in the frequency range

SrCu2(BO3)2.

Frequency-domain
spectroscopy

spinresonance

Frequency-domain electron spin resonance (FDESR)

continuously

frequency-

spectroscopy in the terahertz (THz) region using

electronusing

tunable terahertz photomixers

continuously tunable photomixers was demonstrated.

E. Ohmichi1, Y. Shoji1, H. Takahashi1,2,3, H. Ohta1,2Spectral resolution was greatly improved with the use

1

Graduate School of Science, Kobe Universityof a pair of fiber stretchers. In this setup, the amplitude

2

Molecular Photoscience Research Center, Kobeof the THz electric field was determined at each

University

frequency by externally sweeping the optical path

3

JST-PRESTO

difference, resulting in a spectral resolution of about(Appl. Phys. Lett., 2021)

1-MHz. With this technique, we observed narrow ESR

38

spectra with a 20-MHz linewidth, enabling high-Industrial

Demand”

from

Japan

Scienceandresolution FDESR spectroscopy in a broad frequency Technology Agency (JPMJSK1615) and by therange.

Amada Foundation.

This work was supported by Competitive
Funding Programs “Collaborative Research Based on

Angle-dependent force-detected terahertz ESR(J. Jpn. Soc. Infrared Science & Technology., 2021)

measurement of non-centrosymmetric magnet

It is known that the non-centrosymmetric copper

CuB2O4

metaborate CuB2O4 exhibits nonreciprocal directional

D. Hachiya1, H. Takahashi2,3, T. Arima4, S.

dichroism where the optical absorption changes withToyoda5, M. Saito6, E. Ohmichi1, S. Okubo2 and H.

the reversal of the direction of light propagation.

Ohta2

Such non-reciprocity has also been observed in the1

Graduate School of Science, Kobe University

microwave region.

2

Molecular Photoscience Research Center, Kobe

supposed to originate from its complex magnetic

University

structure, the details still remail unclear.

3

JST-PRESTO

study, we performed angle-dependent force-detected

4

Department of Advanced Materials Science, The

electron spin resonance measurements in the terahertz

Although their origins are
In thisUniversity of Tokyo

region to clarify the magnetic properties of CuB2O4

5

Institute of Physical and Chemical Researchfrom the microscopic viewpoint.

6

Graduate School of Science, Tohoku University

III-C.

DEVELOPMENT AND APPLICATION OF HIGH-PRESSURE THz ESR SYSTEMHigh pressure ESR measurement is very useful for studying the pressure effect of magnetic materials and wehave developed very unique high pressure THz ESR systems so far. For the transmission type system, weestablished a ratio of inner and outer diameters of pressure cell cylinder which generates a pressure beyond
2 GPa repeatedly. The previous pressure cell cylinder had an inner diameter of 4 mm and the inner/outer
diameter ratio of 5.9. By changing the ratio to 7 (the outer diameter to 28 mm) to suppress its deformation
under load, we reduced damage to ceramic internal parts. As a result, we succeeded in observing the pressure
dependence of the direct transition from the singlet ground state to the excited triplet states up to 2.3 GPa for
CuVOF4(H2O)6·H2O, in which the antiferromagnetic dimer units composed of two different S = 1/2 species
Cu2+ and V4+. It was found that the direct transition ESR mode disappeared above 2 GPa. Further
investigation is ongoing to clarify the origin of disappearance for the direct ESR transition mode above 2
GPa. This study is collaboration with Dr. Dmytro Kamenskyi, Augsburg University, Germany.
We also developed high pressure ESR measurement technique based on the thermal detection method, inwhich ESR is observed by detecting the temperature change of the sample at resonance condition. As the ESR

39

probe becomes compact with this method, it can be combined with a various type superconducting magnets. In
this study, we developed a system where we can perform the field angle dependence measurement under highpressure in combination with a split-pair type superconducting magnet. We succeeded in observing detailed
pressure changes in the crystal field of the spin gap substance Cu2(1,4-diazacycloheptane)2Cl4 by this system.
A master course student N. Nagasawa received the excellent presentation award at the 30th annual meeting of
the Japan Society of Infrared Science and Technology on his development of this thermal detection type highpressure ESR system.

High‐Pressure THz ESR

feature of our high-pressure THz ESR system is that

T. Sakurai1, H. Ohta2, S. Hara1, and Y. Saito

our pressure cell ensures the high pressure and wide1

Research Facility Center for Science and Technology, frequency range using ceramics in internal parts,

Kobe University

which are well balanced in terms of toughness and2

Molecular Photoscience Research Center, Kobetransmittance

University

approach allowed to very accurately describe the spin

(Appl. Mag. Res., 2021）

state under pressure. In this review, high-pressure ESR

In solid-state physics, pressure is an essential

systems are reviewed with a focus on those in the high-parameter, which can continuously change thefrequency region.

interaction between electrons. The combination of

In addition, we show diﬀerences between otherterahertz electron spin resonance (THz ESR) withsystems and our system. Moreover, we show thepressure is a powerful approach to clarify the spin state

usefulness of our system by showing application

under pressure from the microscopic point of view,

examples of several magnetic materials of interest.

ofelectromagnetic

waves.

This

especially for quantum mag-nets. The most important

Development of Pressure Calibration Method in

coils set outside the pressure cell. The pressure isHigh‐Pressure THz ESR Systemcalibrated

using

alternating

current(AC)

T. Sakurai1, Y. Yasutani2, H. Sugawara2, S. Okubo3, magnetization measurements of the superconducting
H. Ohta3
1transition temperature of tin set inside the pressure cell

Research Facility Center for Science and Technology, with an ESR sample. The system ﬁts the developed

Kobe University

pressure cell with a wide frequency range of 0.05–0.8

2Faculty of Science, Kobe University

THz. The pressure range was extended to 2.8 GPa. The

3

Molecular Photoscience Research Center, Kobe

ESR system was applied to the well-known cobalt

University

Tutton’s salt (NH4)2Co(SO4)2⋅6H2O , and its g(Appl. Mag. Res., 2021)

principal values at 0 GPa were determined as g1=6.61 ,We have developed a pressure calibration method in

g2=3.05 , and g3=2.94 for the ﬁrst time. Furthermore,

the high-pressure THz ESR system using induction40

we succeeded in observing the large change in these gvalues with pressure.

III-D.

MAGNETIZATION MEASUREMENTS USING SQUID MAGNETOMETER

The installation of SQUID magnetometer in 2010 by a Grant-in-Aid Creative Scientific Research“Development of properties and functionalities by precise control of rare-earth doping” (2007-2011, Prof. Y.
Fujiwara (Osaka University) opened up wide varieties of collaborative researches. From 2010 applicationsof SQUID magnetometer to various material researches spread out continuously. It is also supporting theuser programs of Molecular Photoscience Research Center, Kobe University since 2017. Users of SQUID
magnetometer are Mochida and Takahashi group, Uchino group (Department of Chemistry, Kobe University),
Sugawara and Matsuoka group, and Kotegawa and Tou group (Department of Physics, Kobe University), T.
Sakurai, S. Hara and Y. Saito (Center for Supports to Research and Education Activities, Kobe University).
The magnetic anisotropy of the thin film neodymium magnets is revealed by the magnetization measurements
by K. Koike group in joint researches programs of Molecular Photoscience Research Center, Kobe University.

Effect of Mo monoatomic interlayer on magnetic

The as-deposited films showed soft magnetic

properties

properties

ofin-planeanisotropic

Nd-Fe-

withweak

perpendicularmagnetic

B/Mo/FeCo nanocomposite multilayered films

anisotropy, and after annealing above 650°C, these

Kunihiro Koike1, Kazuki Ohashi2, Takuya Suzuki2,

films showed in-plane magnetic anisotropy, good

Chihiro Okita2, Nobuyuki Inaba2, Hiroaki Kato1,

squareness, and hard magnetic properties with highMasaru Itakura3, Shigeo Hara4, Yu Saito4, Susumu

coercivity of about 8 kOe. The (220) peak of Nd2Fe14B

Okubo4, and Hitoshi Ohta4

was identified in the XRD pattern after annealing of1

AppliedMathematics

andPhysics, Yamagata

the film, which means that the c-axis, which is the easy

University

axis of magnetization, points in the plane of the film,

2

Informatics and Electronics, Yamagata University

consistent with the measurement of the magnetization

3

Interdisciplinary Graduate School of Engineering

curve. The positive peak of ΔM plot of in-plane

Sciences, Kyushu University

direction of the film annealed at 800°C was shown.

4

Molecular Photoscience Research Center, Kobe

This result suggests existence of exchange coupling

University

between the Nd-Fe-B and Fe-Co layers in the in-plane(AIP Advances, 2021)

anisotropic multilayered film with monoatomic Mo

The Nd-Fe-B/Mo/Fe-Co multilayered films oninterlayer.

MgO(001) were fabricated by UHV sputtering method.

41

III-E.

SPIN AND LATTICE DYNAMICS STUDIED BY PUMP-PROBE AND TERAHERTZ
SPECTROSCOPIESThe terahertz region in the electromagnetic spectrum has attracted research attention in solid-state physics,
because elementary excitations in solid-state materials such as phonons and magnons play important roles,
and many of those dynamics appear in this energy region. The ultrafast spin dynamics and optical spin control
in magnetic materials are attractive topics because of the potential applications in the developments ofultrafast spin control, spintronics, quantum computing, and optical control of correlated spin systems. We
studied the spin and lattice dynamics in solid-state materials using optical pump-probe spectroscopy andterahertz time-domain spectroscopy (THz-TDS). The generation and detection of magnetization andbirefringence using optical and electric pulses are very useful to observe the spin and lattice dynamics inferromagnetic, antiferromagnetic, multiferroic, and magnetoelectric materials. The time-domain
spectroscopy has a large potential for the ultrafast, broadband, and accurate observation of elementary
excitation dynamics in the terahertz region.

Longitudinal electric-field induced magnetization

second-order magnetoelectric (ME) effects. Different

in YIG: First- and second-order magnetoelectric

ME domains are generated depending on the relative

effects observed by Faraday rotation

direction of the cooling electric and magnetic fields,

Y. Mushiaki1, H. Nagatomi1, K. Fujimoto1, T.

and the electric-field dependence of the electric-field

Hasunuma1, and T. Kohmoto1,2

induced magnetization shows different curves. Even

1

Graduate School of Science, Kobe University

for fixed directions of the cooling electric and2

Molecular Photoscience Research Center, Kobe

magnetic fields, ME domains with opposite signs were

University

observed, and they are considered to distribute in the(submitted)

sample. Increasing the beam diameter of the Faraday-

We observed the electric-field induced magnetization

rotating probe light reduced the signal amplitude of thedue to the change in the magnitude of magnetizationelectric-field induced magnetization. This behavior

in yttrium iron garnet Y3Fe5O12 (YIG) using Faraday

can be qualitatively explained by a simple model ofrotation, and investigated its behavior with respect tostatistical physics. At low temperatures, the first-order

the applied electric and magnetic fields. It was foundME effect is dominant, but above 200 K, the second-that the magnitude of the electric-field inducedorder ME effect is dominant. It may be considered that,magnetization in YIG is proportional to and is 103

at low temperatures, excess electrons are localized totimes smaller than that of the magnetic-field induced

specific Fe2+ ions formed near oxygen defects to show

magnetization in our experiment. The observed

the first-order ME effect, and that, at highamplitude of the electric-field induced magnetization

temperatures, they are delocalized by electron hopping

can be given by a sum of two components linear andto show the second-order ME effect.

quadratic in the electric field due to the first- and42induced

the temperature increases toward TN ( = 307 K). It

magnetization and the domain switching in an

was confirmed that, when the magnetic field isantiferromagnet Cr2O3

inverted in an electric field and the magnitude of the

S. Kawabata1, A. Okamoto1, Y. Maeda1, and T.

magnetic field exceeds a certain threshold value, theKohmoto1,2

Faraday rotation signal is inverted. This shows that1

Graduate School of Science, Kobe University

the antiferromagnetic domain switching occurs.

2

Molecular Photoscience Research Center, Kobe

The inversion behavior does not change for

University

different laser beam spot sizes. This suggests that(32nd Symp. Assoc. Cond. Matter Photophysics)

the domain switching occurs globally rather than

Dynamics

oftheelectric-field

We studied the dynamics of the electric-field locally. From the observation of the domain
induced magnetization and the domain switching in switching in the millisecond region, it is found thatan antiferromagnet Cr2O3 using the Faraday effect. the domain switching occurs instantaneously in the
The time evolution of the Faraday rotation signal in millisecond range. The domain switching in Cr2O3
the nanosecond region was observed in a pulsed is considered to be a dynamic cooperativeelectric field. The rise time of the electric-field phenomenon in the antiferromagnetic ordered state,induced magnetization was found to be less than the and it can be controlled by the electric field using
response time of our measurement system, 10 ns. the magnetoelectric effect.
The Faraday rotation amplitude becomes smaller as

Observationofmagnetic

Kerrrotationinrotates, to study the electromagnetic effect, crystal axis

magnetite

switching, and magnetic domain switching. We

M. Kita1, Y. Iwasa1, and T. Kohmoto1,2

observed the magnetic-field induced axis switching in

1

Graduate School of Science, Kobe University

the monoclinic crystal by using the axis-dependent2

Molecular Photoscience Research Center, Kobe

shape of the magnetization curve. The axis switching

University

was observed at the temperatures 90, 100 and 110 K,(32nd Symp. Assoc. Cond. Matter Photophysics)

but not observed at 80 K in the magnetic field up to 5

The magnetization in a ferrimagnet Fe3O4 was

T. It is considered that there is a threshold value of theobserved by a magneto-optical effect called magnetic

external magnetic field at each temperature, above that

Kerr rotation, in which the polarization plane of thethe axis switching occurs.

reflected light of a linearly polarized probe light43

Original Papers

発表論文

authors

title

Journal

Vol.

page

year

Hiroshi Imahori, Yasuhiro
Kobori, Hironori KajiManipulation of Charge-Transfer Statesby Molecular Design: Perspective from
“Dynamic Exciton”

Acc. Mater. Res.

2

501–5142021.6.29

Shunta Nakamura, Hayato
Sakai, Masaaki Fuki,
Yasuhiro Kobori, Nikolai
V. Tkachenko, and Taku
HasobeEnthalpy–Entropy Compensation
Effect for Triplet Pair Dissociation of
Intramolecular Singlet Fission in
Phenylene Spacer-Bridged Hexacene
DimersJ. Phys. Chem.
Lett.

12

6457–6463

2021.7.8

Manabu Sakurai, Ryota
Kabe, Masaaki Fuki,
Zesen Lin, Kazuya Jinnai,
Yasuhiro Kobori, Chihaya
Adachi, and Takashi
Tachikawa

Organic photostimulated luminescence
associated with persistent spincorrelated radical pairs

Communications
Materials

2

Articlenumber:74

2021.7.13

Shunta Nakamura, Hayato
Sakai, Hiroki Nagashima,
Masaaki Fuki, Kakeru
Onishi, Ramsha Khan,
Yasuhiro Kobori, Nikolai
V. Tkachenko, and Taku
HasobeSynergetic Role of Conformational
Flexibility and Electronic Coupling for
Quantitative Intramolecular Singlet
FissionJ. Phys. Chem. C

12518287-18296

2021.8.13

Misato Hamada, Tatsuya
Iwata, Masaaki Fuki,
Hideki Kandori, Stefan
Weber, Yasuhiro Kobori

Orientations and water dynamics ofphotoinduced secondary chargeseparated states for magnetoreception
by cryptochrome

Commun. Chem.

41412021.9.30

Taku Hasobe, Shunta
Nakamura, Nikolai V.
Tkachenko, and Yasuhiro
KoboriMolecular Design Strategy for HighYield and Long-Lived Individual
Doubled Triplet Excitons throughIntramolecular Singlet Fission

ACS Energy Lett.

7

390–400

2022

Hiromu Fuse, Yu Irie,
Masaaki Fuki, Yasuhiro
Kobori, Kosaku Kato,
Akira Yamakata, Masahiro
Higashi, Harunobu
Mitsunuma, Motomu
Kanai

Identification of Self-Photosensitizing
Hydrogen Atom Transfer
Organocatalyst System

J. Am. Chem. Soc.

In press

2022

S. Tominaka, I. Karimata,T. Matsuoka, M.
Sakamoto, T. Nakajima, K.
Ohara, T. Tachikawa

Dynamic Symmetry Conversion in
Mixed-Halide Hybrid Perovskite upon
Illumination

ACS Energy Lett.

63858-3863

2021

M. Yamashita, S. Nagai, S.
Ito, T. Tachikawa

In Situ Exploration of StimulusInduced Emission Changes in
Mechanochromic Dyes

J. Phys. Chem.
Lett.

12
(32)

7826-7831

2021

S. Ito, S. Nagai, T.
Ubukata, T. Tachikawa

Multi-color mechanochromic
luminescence of three polymorphic
crystals of a donor-acceptor-type
benzothiadiazole derivative

CrystEngComm.

23
(34)

5899-5907

2021

S. Ito, R. Sekine, M.
Munakata, M. Asami, T.
Tachikawa, D. Kaji, K.
Mishima, Y. Imai

Mechanochromic Luminescence andSolid-State Circularly Polarized
Luminescence of a Chiral DiamineLinked Bispyrene

ChemPhotoChem

5(10)

920-925

2021

44

S. Ito, R. Sekine, M.
Munakata, M. Yamashita,
T. Tachikawa

Mechanochromic Luminescence(MCL) of Purely Organic TwoComponent Dyes: Wide-Range MCL
over 300nm and Two-Step MCL by
Charge-Transfer Complexation

Chem.Eur.J..

27
(56)

1398213990

2021

N. Haraguchi, T. Okunaga,
Y. Shimoyama, N.
Ogiwara, S. Kikkawa, S.
Yamazoe, M. Inada, T.
Tachikawa, S. Uchida

Formation of Mixed-Valence
Luminescent Silver Clusters via
Cation-Coupled Electron-Transfer in a
Redox-Active Ionic Crystal Based on a
Dawson-type Polyoxometalate with
Closed Pores

Eur. J. Inorg.
Chem.

2021

1531-1535

2021.3.18

K. Ogawa, R. Sakamoto,
C. Zhong, H. Suzuki, K.
Kato, O. Tomita, K.
Nakashima, A. Yamakata,
T. Tachikawa, A. Saeki, H.
Kageyama, R. Abe

Manipulation of charge carrier flow in
Bi4NbO8Cl nanoplate photocatalyst
with metal loading

Chem. Sci.,

13
(11)

3118-3128

2022

Z. Zhang, T. Tsuchimochi,
T. Ina, Y. Kumabe, S.
Muto, K. Ohara, H.
Yamada, S. L. Ten-no, T.
Tachikawa

Binary dopant segregation enables
hematite-based heterostructures forhighly efficient solar H2O2 synthesis

Nat. Commun.

13

1499

2022

Feng Zhang, Izuru
Karimata, Houng-Wei
Wang, Takashi Tachikawa,
Keisuke Tominaga,
Michitoshi Hayashi,
Tetsuo Sasaki

Terahertz Spectroscopic Measurements
and Solid-state Density Functional
Calculations on CH3NH3PbBr3
Perovskites-Short-Range order ofMethylammonium

J. Phys. Chem. C

in press

2021

Feng Zhang, Keisuke
Tominaga, Michitoshi
Hayashi, Masahiko Tani

A Quantitative Interpretation for the
Difference of Terahertz Spectra of DLand L-Alanine: Origins of Infrared
Intensities in Terahertz Spectroscopy

J. Phys. Chem. C

DOI:
10.1021/acs.
jpcc.1c0285
42021.7.14

Kaoru Ohta, Yuichi
Hiramatsu, Mitsuharu
Suzuki, Hiroko Yamada,
Keisuke Tominaga

Nature of Local Charge Carrier
Motions in Porphyrin-Based Bulk
Heterojunction Films Revealed byTime-Resolved Optical PumpTerahertz Probe Spectroscopy

Chem. Lett.

in press

2021

Kaoru Ohta

Time-Reversal Focusing of Ultrashort
Pulses through Thin Scattering Media

Optics Express

5486-5497

2022

Erika Mitani, Yukihiro
Ozaki, and Harumi Sato

Two Types of C=O…HO Hydrogen
Bonds and OH…OH (Dimer, Trimer,
Oligomer) Hydrogen Bonds in PVA
with 88% Saponification/PMMA andPVA with 99% Saponification/PMMA
Blends and Their Thermal Behavior
Studied by Infrared Spectroscopy

Polymer

45

(16)

30

in press

Harumi Sato, Yusuke
Morisawa, Satoshi Takaya,
Yukihiro Ozaki

A Study of C=O…HO and OH…OH(Dimer, Trimer, and Oligomer)
Hydrogen Bondings in a Poly(4vinylphenol)30%/Poly(methyl
methacrylate)70% Blend and its
Thermal Behaviour Using Nearinfrared Spectroscopy and Infrared
Spectroscopy and Infrared
Spectroscopy

AppliedSpectroscopy

Huiqiang Lu, Harumi Sato,
Sergei G. Kazarian

Visualization of Inter-andIntramolecular Interactions in Poly(3hydroxybutyrate)/ Poly(L-lacticacid)(PHB/PLLA) Blends During
Isothermal Melt Crystallization Using
Attenuated Total Reflection Fourier
Transform infrared (ATR FT-IR)
Spectroscopic Imaging

AppliedSpectroscopy

750003702821
10102

2021.4.22

Atsushi Nishimae, Harumi
Sato

Study of Co-crystallization andIntermolecular Hydrogen Bondings ofPoly(glycolide-co-L-lactide)
Copolymers by Terahertz and LowFrequency Raman Spectroscopy

Macromolecules

546440-6448

2021.6.16

Mirosław Antoni
Czarnecki, Yusuke
Morisawa, Yukiteru
Katsumoto, Tomoyuki
Takaya, Swapnil Singh,
Harumi Sato and Yukihiro
Ozaki

Solvent Effect on Competition
Between Weak and Strong Interactions
in Phenol Solutions Studied by Nearinfrared Spectroscopy and DFT
Calculations

Phys. Chem.
Chem. Phys.

23

1918819194

2021.8.12

Tulika Sharma, Yoshiaki
Nishio, Yuichiro Tamano,
Harumi Sato, Isao
Takahashi

Correlation of physical aging and glasstransition temperatures in ultrathin
polystyrene films supported on SiO2

Polymer

230

1241032021.9.16

Mao Nochi, Yukihiro
Ozaki, Harumi Sato

Water-induced conformational changes
in the powder and film of εpoly(L)lysine studied by infrared andRaman spectroscopy

Spectrochimica
Acta Part A

260

1199002021.11

T. Sakurai, H. Ohta, S.
Hara, and Y. Saito

High‐Pressure THz ESR（Invitedreview)

Appl. Mag. Res

52

267-2812021.4

E. Ohmichi, T. Okamoto,H. Takahashi, H. Ohta

Mechanically Detected Terahertz
Electron Spin Resonance（Invitedreview)

Appl. Mag. Res.

52

283-304

2021.4S. V. Demishev, A. V.
Semeno, and H. Ohta

Staggered Field in Quantum
Antiferromagnetic S = 1/2 Spin Chain
Probed by High‐Frequency EPR (theCase of Doped CuGeO3)（Invitedreview)

Appl. Mag. Res

52

379-4102021.4

S. Okubo, H. Ohta, T.
Ijima, T. Yamazaki, W.‐M.
Zhang, S. Hara, S. Ikeda,
H. Oshima, M. Takahashi,
K. Tomiyasu, T. Watanabe

THz ESR Study of Peculiar Co
Pyrochlore System GeCo2O4 Using
Pulsed High Magnetic Field

Appl. Mag. Res

52411-4242021.446

in press

A. V. Semeno, S. Okubo,
H. Ohta, and S. V.
Demishev

Heavy Fermion Metal CeB6 in SubTHz
and THz Range: The Electron Spin
Resonance and Neutron Scattering
Studies（Invited review)Appl. Mag. Res

52459-4722021.4

M. Matsumoto, T. Sakurai,
Y. Hirao, H. Ohta, Y.
Uwatoko, and H. Tanaka

First ESR Detection of Higgs
Amplitude Mode and Analysis with
Extended Spin‐Wave Theory in Dimer
System KCuCl3

Appl. Mag. Res

52523-5642021.4

H. Takahashi, T. Sakurai,
E. Ohmichi, H. Ohta

Field-angle-dependent multi-frequency
electron spin resonance spectroscopy insubmillimeter wave range based onthermal detection

Rev. Sci. Instrum

92083901/1-6

2021.8

D. Yamamoto , T. Sakurai,
R. Okuto, S. Okubo, H.
Ohta, H. Tanaka, and Y.
UwatokoContinuous control of classicalquantum crossover by external highpressure in the coupled chain
compound CsCuCl3

NatureCommunications

124263/1-92021.7

T. Sakurai, Y. Yasutani, H.
Sugawara, S. Okubo, H.
Ohta

Development of Pressure Calibration
Method in High‐Pressure THz ESR
SystemAppl. Mag. Res

E. Ohmichi, Y. Shoji, H.
Takahashi, H. Ohta

Frequency-domain electron spinresonance spectroscopy using
continuously frequency- tunableterahertz photomixers

Appl. Phys. Res

119162404/1-5

2021.10

Kunihiro Koike, Kazuki
Ohashi, Takuya Suzuki,
Chihiro Okita, Nobuyuki
Inaba, Hiroaki Kato,
Masaru Itakura, Shigeo
Hara, Yu Saito, Susumu
Okubo, and Hitoshi Ohta

Effect of Mo monoatomic interlayer onmagnetic properties of in-planeanisotropic Nd-Fe-B/Mo/FeCo
nanocomposite multilayered films

AIP Advances

11015134/2021.1

Mitsuru Akaki, Kenta
Kimura, Yasuyuki Kato,
Yuya Sawada, Yasuo
Narumi, Hitoshi Ohta,
Tsuyoshi Kimura,
Yukitoshi Motome, andMasayuki Hagiwara

Nonreciprocal Linear dichroism
observed in electron spin resonancespectra of the magnetoelectric
multiferroic Pb(TiO)Cu4(PO4)4

Physical Review
Research3

L0420432021.1

S. Kimura, H. Onishi, A.
Okutani, M. Akaki, Y.
Narumi, M. Hagiwara, K.
Okunishi, K. Kindo, Z. He,
T. Taniyama, and M. Itoh

Optical selection rules of the magnetic
excitation in the S=1/2 onedimensional Ising-like antiferromagnet
BaCo2V2O8

Phys. Rev. B

1050144172022.1S. P. M. Curley, B. M.
Huddart, D. Kamenskyi,
M. J. Coak, R. C.
Williams, S.
Ghannadzadeh, A.
Schneider, S. Okubo, T.
Sakurai, H. Ohta, J. P.
Tidey, D. Graf, S. J. Clark,
S. J. Blundell, F. L. Pratt,
M. T. F. Telling, T.
Lancaster, J. L. Manson,
and P. A. Goddard

Anomalous magnetic exchange in a
dimerized quantum magnet composedof unlike spin species

Phys. Rev. B

104214435/1-11

2021.9472021.7

D. Hachiya, H. Takahashi,
T. Arima, S. Toyoda, M.
Saito, E. Ohmichi, S.
Okubo and H. Ohta

Angle-dependent force-detectedterahertz ESR measurement of noncentrosymmetric magnet CuB2O4

J. Jpn. Soc.
Infrared Science& Technology

31
NO.
1

K. Aoyama and
H. Kawamura

Effects of spin-lattice coupling and amagnetic field in classical Heisenberg
antiferromagnets on the breathing
pyrochlore lattice

Phys. Rev. B

104

1844112021.8K. Mitsumoto and
H. Kawamura

Replica symmetry breaking in the
RKKY skyrmion-crystal system

Phys. Rev. B

1041844322021.8

K. Uematsu, T. Hikihara,and H. Kawamura

Frustration-induced quantum spin
liquid behavior in the s = 1/2 randombond Heisenberg antiferromagnet on
the zigzag chain

J. Phys. Soc. Jpn.

90

124703/1-10

2021.11Y. P. Mizuta, K.
Aoyama, K. Tomiyasu, M.
Matsuura, and H.
Kawamura

Spin Dynamics Simulation of the Z2vortex Fluctuations

J. Phys. Soc. Jpn.

91

0350012022.2

K. Mitsumoto and H.
Kawamura

Skyrmion crystal in the RKKY systemon the two-dimensional triangularlatticePhys. Rev. B

1050944272022.3

K. Tomiyasu, Y. P. Mizuta,
M. Matsuura, K. Aoyama,and H. Kawamura

Observation of topological Z2 vortex
fluctuations in the frustrated
Heisenberg magnet NaCrO2(ar Xiv)

48

2021

2021.10

Invited Talks (domestic and international)
発表者
氏名

開催
時期

開催地

Plenary

招待講演(国内および国際研究集会)

学会名

講演題目

or
invite2021
6. 4

onlineinviteECS Meeting

Vibronic Effect of Donor-Acceptor Interaction
Determines Fate of Mutiexciton Spins Generated
By Singlet Fission

2021.
12. 18

onlineinvite7th Kanto Area Spin
Chemistry Meeting(KASC 7)

Water dynamics control of the magnetic compass

2021.
9. 7

onlineinvite

第一回広帯域極限電磁波
生命理工連携研究会「電子スピン分極映像化による超高効率光エネ
ルギー変換機構の解明」

2021.
9. 9

onlineinvite

第 19 回 ESR 夏の学校講演会「電子スピン分極映像化による超高効率光エネ
ルギー変換機構の解明」

2021.
9.16

onlineinvite量子生命科学会第 3 回大会

光合成光電荷分離のスピン量子コヒーレンスとデコヒーレンス

2021.
10.1

onlineinviteICFPE2021

Conformation change and electronic de-coupling
via intramolecular singlet fissions

2021.
11.1

onlineinviteModern Development ofMagnetic ResonanceVibronic Spins in Singlet Fissions

2021.
11.26

onlineinvite

第 15 回物性科学領域横断研究会

動物の磁気コンパスにおける水和運動の役割:
光受容タンパク質の長距離電荷分離機構

2021.
12.17

onlineinvitePacifichem2021

Spin-entanglement transport via singlet-fission as
studied by transient EPR

2021.
12.19

onlineinvitePacifichem2021

Heterogeneous charge-separation geometries atbulk-heterojunction interfaces in organic solar
cell studied by transient EPR

2022.
1.28

京大桂キ
ャンパス

invite京都大学分子工学研究科
特別講演会

電子スピン分極の空間映像化による動的エキシトン機構解析

2022.
3.25

onlineinvite

日本化学会春季年会特別企画「光化学の新展開」

電荷移動によるスピンの動きを捉える

岡本翔
T.
Okamoto

2022.
3.16

onlineinvite

第二回広帯域極限電磁波
生命理工連携研究会

光線力学療法への応用に向けた新しい光アップ
コンバージョン材料の開発

婦木正明
M. Fuki

2021.
7.28

onlineInvite

第 4 回動的エキシトン若
手セミナー

分子内一重項励起子分裂における一重項－五重項変換および解離のスピンダイナミクス

立川貴士
T.
Tachikawa

2021.11. Korea
1-4(online)invite11th Asian Photochemistry
Conference

Development of hematite mesocrystal-based
photoanodes for solar fuel production

富永圭介
K.
Tominaga

2021.5.
10-12

invite

ガラスおよび関連する複雑系の最先端研究水和したソフトマターの広帯域誘電分光

小堀康博
Y. Kobori

東京大学
物性研究
所

49

2021.11. Korea
1-4(online)invite11th Asian Photochemistry
Conference

Ultrafast Charge Carrier Dynamics in
Tetrabenzoporphyrin Derivatives Studied byTime-resolved Terahertz Spectroscopy

2021.11. Mumbai,
12-14
India
(online)inviteUltrafast Science (UFS) 2021

THz Molecular Science in Condensed Phases

2021.5.
15-16

onlineinvite

第 16 回 ESR 入門セミナー

超入門2021.8.
22-27

onlineinvite22nd International Societyof Magnetic ResonanceConference
9th Asia-Pacific NMR
Symposium (APNMR9)ISMAR-THz 2021

Multi-extreme THz ESR: Recent Developments
and Applications

2021.8.
29-9.3

onlineinviteThe International Societyof Infrared, Millimeter, andTerahertz Waves(IRMMW-THz 2021)

Multi-Extreme THz ESR At The Present Stage

2021.10. online
21-22

invite

第 30 回(2021 年度)日本
赤外線学会研究発表会

多重極限 THz 電子スピン共鳴測定装置の開発2021.11. online
1-5

inviteModern Development ofMagnetic Resonance

Multi-extreme THz ESR: Current Status andFuture2021.12. online
16-21

invite2021 International
Chemical Congress ofPacific Basin Societies

Developments of highly-sensitive mechanicallydetected THz ESR for micro-size single crystals

大久保晋
S. Okubo

2021.11. online
1-5

inviteModern Development ofMagnetic Resonance

Multi-Frequency ESR Study of S=1/2
Antiferromagnetic Chain with Staggered Field
System KCuMoO4(OH) by Force Detection ESR
Method Using Single Microcrystal

髙橋英幸H.
Takahashi

2021.
4.8

onlineinviteテラヘルツ波科学技術と産業開拓第 182 委員会

テラヘルツ領域における機械検出型磁気共鳴法

赤木暢
M. Akaki2021.9.
20-23

onlineinvite日本物理学会 2021 年秋季大会

パルス強磁場電子スピン共鳴によるスピン多極子の観測2022.3.
15-19

onlineinvite日本物理学会第 77 回年次大会

パルス強磁場を用いた電気磁気効果の研究

光元亨汰
K.
Mitsumoto2021.12. ハイブリッ Oral
ド（神戸国
22-23
際会議場）

International Conference
on Frustration, Topology,
and spin Textures

Chiral-degenerate skyrmion crystal in frustrated
RKKY Heisenberg model

川村光
H.
Kawamura

2021.12. online
22-23

inviteInternational Conference
on Frustration, Topology,
and Spin Textures

Frustration-induced spin textures

onlineinvite令和 3 年度神戸大学分子
フォトサイエンス研究セ
ンター共同利用共同研究
成果報告会

フラストレーションが創るスピンテクスチャ

太田仁
H. Ohta

2022.
3.8

50

Presentation at conferences (international and domestic)

一般講演

学会名

講演題目

オンライン

2021 年光化学討論会

結晶性薄膜の一重項励起子分裂：活性化多重励起子の構造と解離に対す
る動的効果

2021.
9. 19

オンライン

第 15 回分子科学討論会

分子内励起子分裂に伴う立体構造変化と電子的デカップリング：
電子スピン分極映像化による解析

2021.8.
22-27

オンライン

ISMAR-APNMR2021

Geometries and Oscillating Motions
Driving Quintet Multiexcitons andTriplet-Triplet Dissociations via theIntramolecular Singlet Fissions

2021.9.
14-16

オンライン

2021 年光化学討論会

テトラセン分子ワイヤーにおける一重項励起子分裂で生成した多重励起子のスピンダイナミクス

岡本翔
2021.
T. Okamoto 10.21-22

オンライン

第 30 回日本赤外線学会研究発表会

メンブレン型メカニカルセンサーを用いた微量溶液試料向け THz-ESR 装置の開発

2022.3.
23-25

オンライン

日本化学会第 102 春季年会
(2022)

電子スピン共鳴法を用いた有機半導体
光アップコンバージョン材料のドナー/ア
クセプター界面で生成する三重項励起子のダイナミクス

2021.
9.14

オンライン

Oral

2021 年光化学討論会

有機材料を用いた輝尽発光システム
の開発

2021.
12.2

オンライン

Oral

第 40 回固体・表面光化学討論会

ハロゲン交換反応による有機無機ペ
ロブスカイトナノ粒子の構造変換

笠原俊二
S. Kasahara

2021.9.
18-21

札幌（オンライン）

Poster

第 15 回分子科学討論会

14

NO2 および 15NO2 ラジカルの高分解能レーザー分光

馬場正昭
M. Baba

2021.6.
21-25

オンライン

Oral

2021 International Symposium
on Molecular Spectroscopy

Ro-vibrationally averaged molecular
structure of benzene I. Almost the samebond lengths for the C–H and C–D
bonds

2021.6.
21-15

オンライン

Oral

2021 International Symposium
on Molecular Spectroscopy

High-resolution and high-precision laser
spectroscopy of α-benzanthracene

2021.9.
18-21

札幌（オンライン）Oral

第 15 回分子科学討論会

ベンゼンの振動平均構造： Planar but
Non-flat Structure

2021.
5.26

オンライン

Poster

第 70 回高分子学会年次大会

低波数ラマン分光法を用いたスチレン
アクリロニトリル共重合体の熱挙動に関
する研究

2021.
5.26

オンライン

Poster

第 70 回高分子学会年次大会

赤外分光法及び量子化学計算によるポリブチレンサクシネートの分子間水素結
合の検討

2021.
5.27

オンライン

Poster

第 70 回高分子学会年次大会

振動分光法を用いた PVA/PMMA ブレ
ンドの分子間相互作用に関する研究

発表者
氏名

開催
時期

開催地

小堀康博
Y. Kobori

2021.
9. 15

婦木正明
M. Fuki

立川貴士
T.
Tachikawa佐藤春実
S. SatoOral orPoster51

太田仁
H. Ohta

2021.12.
1-3

オンライン

PosterAsia-Pasific Conference on
Condensed Matter Physics 2021

Development of Multi-Extreme THx
ESR system and Its Applications in
Kobe

大久保晋
S. Okubo

2021.5.7

オンライン

Oral

第七回強磁場実験入門セミナー

強磁場発生の歴史

2021.8.
22-27

オンライン

Poster22nd International Society ofMagnetic ResonanceConference
9th Asia-Pacific NMR
Symposium (APNMR9)ISMAR-APNMR2021

Multi-frequency Force Detection ESR
measurements of Single Microcrystal
KCuMoO4(OH) As S=1/2
Antiferromagnetic Chain with Staggered
Field system

2022.3.
15-19

オンライン

Oral

日本物理学会第 77 回年次大会

S=1/2 反強磁性鎖 KCuMoO4(OH)の単結晶 ESR 測定 IV

2021.8.
22-27

オンライン

Poster22nd International Society ofMagnetic ResonanceConference
9th Asia-Pacific NMR
Symposium (APNMR9)ISMAR-APNMR2021

Development of the field-angledependent high-frequency ESR
spectroscopy based on thermal detection
method

2021.
9.24

オンライン

Oral

第八回西日本強磁場科学研究会

熱検出型高周波 ESR 法の開発と応用

2021.8.
22-27

オンライン

Poster22nd International Society ofMagnetic ResonanceConference
9th Asia-Pacific NMR
Symposium (APNMR9)ISMAR-APNMR2021

Pulsed High-field ESR Study ofElectromagnons in Multiferroic
Sr2CoSi2O7

2021.12.
17-18

ハイブリッ
ド（新温泉
町立文化会
館）

Oral

第 16 回量子スピン系研究会

Sr2CoSi2O7 におけるマグノンと 3 マ
グノン

2021.9.
20-23

オンライン

Oral

日本物理学会 2021 年秋季大会

三角格子上の二次元 RKKY ハイゼン
ベルク模型のスカーミオン格子相2021.12.
17-18

ハイブリッ
ド（新温泉
町立文化会
館）

Oral

第 16 回量子スピン系研究会

RKKY 系におけるフラストレーショ
ン誘起のスカーミオン格子相2022.3.
15-19

オンライン

Oral

日本物理学会第 77 回年次大会

RKKY ハイゼンベルク模型における
Z2 渦

嵯峨慎
M. Saga

2022.3.
23-26

オンライン

Oral

日本化学会第 102 春季年会
(2022)

Co(II/III)錯体の反応性の違いを利用した還元剤の分析法の開発

川村光H.
Kawamura

2021.12.
17-18

ハイブリッ
ド（新温泉
町立文化会
館）

Oral

第 16 回量子スピン系研究会

Randomness-induced quantum spin
liquid in the nuclear magnetism of 2D
3He

髙橋英幸
H.
Takahashi

赤木暢
M. Akaki

光元亨汰K.
Mitsumoto

52

大道英二
（理学研
究科）
E. Ohmichi

2021.8.
22-27

オンライン

Poster22nd International Society ofMagnetic ResonanceConference
9th Asia-Pacific NMR
Symposium (APNMR9)ISMAR-APNMR2021

Terahertz Electron Paramagnetic
Resonance Spectroscopy Using Compact
Frequency-Tunable Photomixing
Devices

櫻井敬博
(研究基盤
センター)
T. Sakurai

2021.8.
22-27

オンライン

Poster22nd International Society ofMagnetic ResonanceConference
9th Asia-Pacific NMR
Symposium (APNMR9)ISMAR-APNMR2021

Development of Multi-extreme THz
ESR System and Its Application to
Cobalt Tutton's Salt

2021.9.
20-23

オンライン

Poster日本物理学会 2021 年秋季大会

圧力下 THz ESR 装置における圧力較
正手法の開発と応用 II

2022.
3.10

オンライン

Oral

2021 年度福井大学遠赤外領域開発研究センター共同研究
成果報告会

ESR 測定に適した圧力セル内部部品のジャイロトロンセラミックス焼結装置による作製

2022.3.
15-19

オンライン

Poster日本物理学会第 77 回年次大会

スピンギャップ系物質 Cu2(C5H12N2)2Cl4の圧力効果

2022.3.
15-19

オンライン

Poster日本物理学会第 77 回年次大会

BaCo2(SeO3)3・3(H2O)単結晶育成と磁気異方性測定

原茂生
(研究基盤
センター)
S. Hara53

Presentation by Graduate Students and Postdocs

院生、ポストドクの学会発表

指導教員

発表者氏名

学
年

開催
時期

学会名

講演題目

小堀康博
Y. Kobori

長友敬晃

M2

2021.8.
22-27

ISMAR-APNMR2021

Generation domain of quintet multiexcitons via
singlet fission in organic thin films as studied bytime-resolved EPR

長友敬晃

M2

2021.9.
14-162021 年光化学討論会

ベンゾポルフィリン－ジケトピロロピロールをドナーとするバルクヘテロ接合界面の電荷移動と電荷解離：時間分解 EPR による解析

大西翔

M1

2021.9.
14-162021 年光化学討論会

時間分解 EPR によるビフェニル連結テトラセン
ダイマーの分子内励起子分裂機構の解明

勝平譲治

M1

2021.9.
14-162021 年光化学討論会

時間分解 EPR 法による熱活性化遅延蛍光分子の励起状態の解析

勝平譲治

M1

2022.3.
23-25

日本化学会第 102 春季
年会(2022)時間分解 EPR 法による熱活性化遅延蛍光分子の励起状態の解析

楠本遼太

B4

2022.3.
23-25

日本化学会第 102 春季
年会(2022)分子内一重項励起子分裂で生成する多重励起子の構造変化：時間分解 EPR 法による解析

村山加純

B4

2022.3.
23-25

日本化学会第 102 春季
年会(2022)

時間分解電子スピン共鳴法による非フラーレン型太陽電池材料の界面電荷分離構造解析

清水暘

M2

2021.6.
21-25

2021 International
Symposium on Molecular
Spectroscopy

High-resolution Laser spectroscopy of transstilbene : Nonplanar structure in the ground state

中島康輔

M2

2021.6.
21-25

2021 International
Symposium on Molecular
Spectroscopy

Ultrahigh-resolution Laser spectroscopy ofacetaldehyde: Torsion-inversion-rotationinteraction in the excited state

清水暘

M2

2021.9.
18-21

第 15 回分子科学討論会

trans-スチルベンの S1←S0 遷移の超高分解能
レーザー分光中島康輔

M2

2021.9.
18.21

第 15 回分子科学討論会

高分解能レーザー分光によるアセトアルデヒドの大振幅振動にかんする研究

藤井悠生

D1

2021.6.
13-18

Time Resolved Vibrational
Spectroscopy 2021

Vibrational Frequency Fluctuation of CarbonylCompounds in Water Studied by TwoDimensional Infrared Spectroscopy

高本和也

M2

2021.9.
14-16

光化学討論会時間分解分光法による 9‐アリールカルバゾー
ルの電荷移動状態に及ぼす溶媒効果

藤井悠生

D1

2021.9.
18-21

分子科学討論会

二次元赤外分光法による水溶液中における振動数揺らぎに芳香環が及ぼす影響の解明

藤井悠生

D1

2021.10.
21-22

日本赤外線学会研究発
表会

二次元赤外分光法による水溶液中における振動数揺らぎに対する炭化水素基の影響

笠原俊二
S.
Kasahara

富永圭介
T.
Tominaga54

太田仁
T. Ohta

藤井悠生

D1

2021.10.
28-29

第 43 回溶液化学シンポ
ジウム

二次元赤外分光法による水溶液中における振動数揺らぎの温度依存性

高本和也

M2

2021.10.
28-29

第 43 回溶液化学シンポ
ジウム

フェムト秒過渡吸収分光法による 9-アリールカ
ルバゾールの分子内電荷移動ダイナミクス

井岡光

M1

2021.10.
28-29

第 43 回溶液化学シンポ
ジウム

広帯域分光測定による温度応答性高分子の水和ダイナミクス藤井悠生

D1

2021.10.
31-11.4

11th Asian Photochemistry
Conference

Temperature Dependence of Vibrational
Frequency Fluctuation of Solutes in Water
Studied by Two-Dimensional Infrared
Spectroscopy

井岡光

M1

2021.10.
31-11.4

11th Asian Photochemistry
Conference

Hydration Dynamics of Thermo-responsive
Polymers Investigated by Broadband
Spectroscopy

高本和也

M2

2021.12.
22-23溶液化学研究会若手の会第１回冬季発表会

時間分解分光法及び量子化学計算による 9アリールカルバゾールの分子内電荷移動状態
に対する溶媒効果

藤井悠生

D1

2021.
12.24

神戸大学研究基盤センタ
ー若手フロンティア研究会 2021

二次元赤外分光法による水溶液中における振動数揺らぎの温度依存性

高本和也

M2

2021.
12.24

神戸大学研究基盤センタ
ー若手フロンティア研究会 2021

時間分解分光法及び量子化学計算による 9-ア
リールカルバゾールの分子内電荷移動反応

井岡光

M1

2021.
12.24

神戸大学研究基盤センタ
ー若手フロンティア研究会 2021

温度応答性高分子の水和ダイナミクス

小路悠斗

M2

2021.8.
22-27

22nd International Societyof Magnetic ResonanceConference
9th Asia-Pacific NMR
Symposium (APNMR9)

High-Resolution Frequency-Domain Electron
Paramagnetic Resonance Spectroscopy in the
Terahertz Region

長澤直生

M1

2021.8.
22-27

22nd International Societyof Magnetic ResonanceConference
9th Asia-Pacific NMR
Symposium (APNMR9)

Application of Thermal Detection Method toHigh Pressure THz ESR Measurement

竹原良祐

M2

2021.8.
22-27

22nd International Societyof Magnetic ResonanceConference
9th Asia-Pacific NMR
Symposium (APNMR9)

High-pressure ESR Study on Pressure-induced
Nonmagnetic-magnetic Transition in Spin Gap
System Cu2(C5H12N2)2Cl4

増田祥大

M1

2021.8.
22-27

22nd International Societyof Magnetic ResonanceConference
9th Asia-Pacific NMR
Symposium (APNMR9)

High-Frequency Electron Paramagnetic
Resonance Technique for Spectroscopic Studies
of Metalloproteins under Pressure

小路悠斗

M2

2021.8.29- The International Society
9.3
of Infrared, Millimeter,
and Terahertz Waves(IRMMW-THz 2021)

High-Resolution Frequency-Domain Terahertz
Spectroscopy And Its Application To Electron
Paramagnetic Resonance

55

河本敏郎
T.
Kohmoto竹原良祐

M2

2021.9.
20-23

日本物理学会 2021 年秋季

スピンギャップ系物質 Cu2(C5H12N2)2Cl4 における圧力誘起非磁性-磁性転移

小路悠斗

M2

2021.9.
20-23

日本物理学会 2021 年秋
季

連続波長可変テラヘルツ光源を用いた周波数
掃引型反強磁性共鳴分光法の開発

長澤直生

M1

2021.9.
20-23

日本物理学会 2021 年秋
季

熱的検出による高圧力下 ESR 測定手法の開発
と応用

小路悠斗

M2

2021.9.24

第八回西日本強磁場科学研究会

連続波長可変テラヘルツ光源を用いた周波数
掃引型反強磁性共鳴分光法の開発

竹原良祐

M2

2021.9.24

第八回西日本強磁場科学研究会

スピンギャップ系物質 Cu2(C5H12N2)2Cl4 における圧力誘起非磁性-磁性転移

小路悠斗

M2

2021.10.
21-22

第 30 回(2021 年度)日本
赤外線学会研究発表会

連続波長可変テラヘルツ光源による高分解能
周波数領域電子スピン共鳴法の開発

増田祥大

M1

2021.10.
21-22

第 30 回(2021 年度)日本
赤外線学会研究発表会

圧力下におけるタンパク質の高周波電子スピン
共鳴分光

仲恭平

M2

2021.10.
21-22

第 30 回(2021 年度)日本
赤外線学会研究発表会

55T パルス磁石を用いたテラヘルツ光 ESR 装
置の開発

長澤直生

M1

2021.10.
21-22

第 30 回(2021 年度)日本
赤外線学会研究発表会

熱的検出による高圧力下 ESR 測定手法の開発
と応用

伊神早紀

M2

2021.10.
21-22

第 30 回(2021 年度)日本
赤外線学会研究発表会

ディスク型 WGM 共振器の製作と評価

深川韻

M1

2021.10.
21-22

第 30 回(2021 年度)日本
赤外線学会研究発表会

低温における ESR 測定の感度向上を目的としたマイクロデバイス作製

竹原良祐

M2

2021.10.
21-22

第 30 回(2021 年度)日本
赤外線学会研究発表会

スピンギャップ系物質 Cu2(C5H12N2)2Cl4 の圧力
下 THz ESR 測定

小路悠斗

M2

2021.
12.24

若手フロンティア研究会
2021

連続波長可変テラヘルツ光源を用いた高分解能周波数領域電子スピン共鳴法の開発

長澤直生

M1

2021.
12.24

若手フロンティア研究会
2021

熱検出型高圧下 ESR 測定手法の開発

長澤直生

M1

2022.3.
15-19

日本物理学会第７７回年
次大会

熱的検出による高圧下角度回転 ESR 測定手
法の開発

小路悠斗

M2

2022.3.
22-26

第 69 回応用物理学会春季学術講演会

連続波長可変テラヘルツ光源を用いた周波数
掃引型電子スピン共鳴法の開発と応用

川端将馬

M2

2021.10.
13-15

日本分光学会年次講演会

反強磁性体 Cr2O3 における電場誘起磁化のダ
イナミクス

喜多将之

M2

2021.10.
13-15

日本分光学会年次講演会

マグネタイトにおける磁気カー回転の観測

虫明侑一郎

M2

2021.10.
13-15

日本分光学会年次講演会

YIG における光励起キャリアの拡散ダイナミクス

喜多将之

M2

2021.12.
10-11

第 32 回光物性研究会

マグネタイトにおける磁気カー回転の観測

56

虫明侑一郎M2

2021.12.
10-11

第 32 回光物性研究会

YIG における光励起キャリアの拡散ダイナミクス

川端将馬

M2

2021.12.
10-11

第 32 回光物性研究会

反強磁性体 Cr2O3 における電場誘起磁化とドメ
インスイッチのダイナミクス

喜多将之

M2

2021.
12.24

若手フロンティア研究会

マグネタイトにおける磁気カー回転の測定

虫明侑一郎

M2

2021.
12.24

若手フロンティア研究会

YIG における光励起キャリアの拡散ダイナミクス

川端将馬

M2

2021.
12.24

若手フロンティア研究会

反強磁性体 Cr2O3 における電場誘起磁化とドメ
インスイッチのダイナミクス

虫明侑一郎

M2

2022.3.
15-19

日本物理学会第 77 回年
次大会

YIG における光励起キャリアの拡散ダイナミクス

川端将馬

M2

2022.3.
15-19

日本物理学会第 77 回年次大会

反強磁性体 Cr2O3 における電場誘起磁化とドメ
インスイッチのダイナミクス

57Books著者（共著者も含む）

著書
書名

出版社名

58

ページ数

発行年

Other Publications

参考論文・記事・報告

著者

タイトル

出版物名

巻･号･ページ

発行年

喜多将之、岩佐祐里奈、
河本敏郎

マグネタイトにおける磁気カー回転の観測

光物性研究会論文集

32 巻・43-46

2021

虫明侑一郎、永富寛弥、
川井恵介、河本敏郎

YIG における光励起キャリアの拡散ダイ
ナミクス

光物性研究会論文集

32 巻・115-118

2021

川端将馬、岡本淳、
前田悠貴、河本敏郎

反強磁性体 Cr2O3 における電場誘起磁化とドメインスイッチのダイナミクス

光物性研究会論文集

32 巻・191-194

2021

59

Lecture to Public
氏名
小堀康博

笠原俊二

富永圭介

講演、模擬授業など

講演題目
光電荷分離の動的効果：電子
スピン分極による解明

集会名
第 19 回 ESR 夏の学校

日時
2021.9.
8-10

場所
オンライン

時間分解電子スピン共鳴法を用いた光化学過程の動的機構解明
温室ガス効果ってなーに？

京都大学分子工学研究科分子工学特論第三（後半）集中講義

2022.1.
27-28

京都大学桂キャンパス

第 16 回女子中高生のための関西科学塾

2021.11.7

オンライン

Vibrational Spectroscopy andGlobal Warming

学部生向け授業

2022.3.23 タイ・タンマサート大学シリントーン国際工学部

60

Awards
氏名

受賞
受賞研究題目立川貴士

賞名団体、学会名令和 3 年度学長表彰

国立大学法人神戸大学

太田仁

多重極限 THz 電子スピン共鳴測定装置の開発

第 6 回業績賞

日本赤外線学会

高本和也

時間分解分光法及び量子化学計算による 9-アリールカルバゾールの分子内電荷移動状態に対する溶媒効果

優秀発表賞

溶液化学研究会若手の会第 1 回冬季発表会

北原遥子、原茂生、櫻井敬博、大久保晋、太田仁、木村史子、木村恒久、那波和宏、岡本
佳比古、廣井善二

NaCuMoO4(OH)の磁場中配向試料によるテラヘルツ ESR 測定

第 7 回論文賞

日本赤外線学会

小路悠斗

連続波長可変テラヘルツ光源を用いた周波数掃引型反強磁性共鳴分光法の開発

ポスター賞

第八回西日本強磁場
科学研究会

赤木暢

パルス強磁場を用いた電気磁気効果の研究

第 16 回(2022 年)日本物理学会若手奨励賞

日本物理学会

長澤直生

熱的検出による高圧下 ESR 測定手法の
開発と応用

優秀発表賞

第三十回日本赤外線学会研究発表会

小路悠斗

連続波長可変テラヘルツ光源を用いた高分解能周波数領域電子スピン共鳴法の開発

極低温部門賞

若手フロンティア研究会
2021

小路悠斗

周波数掃引型テラヘルツ領域電子スピン共鳴分光法の開発

優秀発表賞

修士論文審査会

伊神早紀

Whispering gallery mode センシングデバ
イス開発に向けたディスク型共振器の作
製

優秀発表賞

修士論文審査会

61Conference Organization
氏名

学術集会

立川貴士

学術集会の開催
共同主催者

場所

時期

参加者
概数

先端融合研究環 開拓プロジェ
クト「階層縦断的アプローチ
による革新的光エネルギー変換系の開拓」最終シンポジウ
ム

オンライン

2022.3.4

約 40
名

笠原俊二

日本分光学会関西支部講演会

オンライン

2022.3.2

30 名

富永圭介

第 2 回広帯域極限電磁波生命
理工連携研究会「光線力学療法・光免疫療法の進展と光分子科学研究の展開」

オンライン

2022.
3.16

55 名

太田仁
大久保晋
大道英二

ISMAR-APNMR2021

ISMAR-APNMR-NMRSJSEST2021 合同会議組織委員会
国際磁気共鳴学会
アジア太平洋核磁気共鳴学会
日本核磁気共鳴学会
電子スピンサイエンス学会

オンライン
（大阪）

2021.8.
22-27

920 人

太田仁
大久保晋

第 16 回量子スピン系研究会

分子フォトサイエンス研究センター

ハイブリッ 2021.12.
ド（新温泉 17-18
町立文化会
館）

95 人

川村光
太田仁
大久保晋

International Conference on
Frustration, Topology, and Spin
Textures

科学研究費補助金 基盤 S
「フラストレーションを創る
スピンテクスチャ」
代表者 川村光

ハイブリッ 2021.12.
ト（神戸国 22-23
際会議場）

180 人

62

Seminars

セミナー

Date
2021.12.11

Name
光元亨汰

Affiliation
分子フォトサイエンス研究
センター

Title
外的な乱れのない系におけるレプリカ対称性の破れ

2021.12.11

嵯峨慎分子フォトサイエンス研究センター

金属錯体よもやま話63

Molecular Photoscience Research Center
Kobe University,
Nada, Kobe 657-8501 Japan
Tel: +81-78-803-5761
URL: http://www.research.kobe-u.ac.jp/mprc/about/index_e.html (English)〒657-8501
神戸市灘区六甲台町 1－1
神戸大学分子フォトサイエンス研究センター
電話番号 078-803-5761
http://www.research.kobe-u.ac.jp/mprc/index.html （日本語）